April 15 is the Day of Criminal Investigation Workers in Ukraine, the World Art Day, the International Day of the Biomedical Laboratory and the International Day of Microvolunteering. The commemorative events of April 15 are a palette of historical moments that touch on politics, culture, music, wars and tragedies that occurred in different eras, but on this particular day left their mark in the collective memory.
Day of criminal investigation workers in Ukraine
This is a professional holiday dedicated to people who work in the shadows, do not have the right to publicity, but every day save lives, fight crime, solve murders, search for particularly dangerous criminals and help to establish justice.
This holiday appeared in Ukraine relatively recently. In 2018, the Ministry of Internal Affairs of Ukraine, by its order No. 320, established the date of April 15 as the official Day of criminal investigation workers. The idea was to pay tribute to one of the oldest and most important divisions of the law enforcement system – criminal investigation.
The date was chosen because it was on April 15, 1919 that the criminal investigation service was created in the system of the People’s Commissariat of Internal Affairs. In Ukraine, this direction of work began to take shape from the first years of Soviet power, but was preserved and transformed during the period of independence. And although the methods, technologies, and legal framework have undergone radical changes, the main task has remained unchanged — the detection of serious and especially serious crimes.
Criminal investigation is not an office job. Employees of this unit are often the first to arrive at the crime scene, conduct an operational investigation, work undercover, interact with the agency, and make arrests. Their work is a constant risk, tension, psychological stress, and sometimes a real hunt for a dangerous criminal. Criminal investigation is often associated with cinematic images: shadowy figures in civilian clothes who speak briefly, act decisively and do not divulge details. But behind this romanticized picture is hard work, many years of experience, intuition and deep knowledge of the criminal world.
Interesting facts
The first detective department in history is considered to be Surte in France, created in 1812. It was founded by ex-criminal Eugène Francois Vidoc, who managed to reform the police from within, using his knowledge of the criminal world.
One of the first methods of forensic identification – bertillonage – used anthropometric data. It was used in the 19th century to identify criminals, before fingerprints were introduced.
In Ukraine, the first official criminal investigation unit was created in Kharkiv back in 1920. Systematic implementation of crime fighting methods began from there.
Operatives are looking not only for criminals, but also for missing persons. Thanks to criminal investigations, thousands of missing people are found in Ukraine every year, including children, victims of human trafficking, and missing military personnel.
Criminal investigation is a division in which intuition is especially valued. Often it is the “sixth sense” that allows you to identify a criminal when there are no traces or direct evidence.
World Art Day
This day is determined by the birthday of Leonardo da Vinci, a genius who embodies the ideal of the Renaissance artist. In 2012, UNESCO and the International Association of Arts (IAA) initiated the establishment of World Art Day to celebrate the power of art to enrich human culture, inspire, unite people and protect the rights to creative freedom. Since then, April 15 has become a day when museums, galleries, theaters, art centers and art schools all over the world hold open events, performances, lectures, street exhibitions, art marathons and online projects.
Art, as stated in UNESCO documents, is a universal language capable of overcoming cultural barriers, healing the soul, shaping critical thinking and increasing society’s resilience to violence, intolerance and misinformation.
In the world of wars, epidemics, climate crises, art acquires a new meaning:
— as a form of resistance that speaks the truth when others are silent;
— as a tool for healing the psyche, when traditional methods do not work;
— as a space of freedom where every person can express his identity and voice.
In Ukraine, this is especially relevant — artists, painters, theatergoers, musicians, and photographers have become chroniclers of war reality, turning pain into an image, and tragedies into a call to action, memory, and resilience.
Interesting facts
The world’s first modern art museum was on a steamship. In 1924, the Soviet experimental “Museum of Living Art” floated down the Volga and exhibited paintings in villages.
In “The Last Supper” by Leonardo da Vinci, the food on the table corresponds to the real menu of the 15th century – crustless bread, baked fish and fruit eaten in the monasteries of Milan. These are not just symbols – they are a reconstruction of the meal.
On the original of Van Gogh’s “Starry Night” traces of a brush stroke are visible, made in a state of mental aggravation – studies show that the movement of the artist’s hand was uneven, rhythmically distorted.
The painting “Black Square” by Malevich has microcracks in the upper layer, under which another painting was discovered. Initially, it was a composition of cubo-futuristic figures – that is, Malevich himself “crossed out” the previous work.
In the Sistine Chapel, the figure of God creating Adam exactly follows the anatomical outline of the human brain. This coincidence was discovered by a neurosurgeon in the 1990s: Michelangelo, who dissected bodies, may have deliberately hidden the symbol of the mind.
Restorers found the remains of an eyebrow and an eyelash in the Mona Lisa. They faded not because Leonardo did not paint them, but because of centuries of cleaning and improper restorations.
When Caravaggio’s Judith Killing Holofernes was first exhibited, visitors felt sick. The realism of the scene was so strong that it was compared to public executions.
In the Japanese engraving art of the 18th century. used poisonous paints. Shades of red and green contained arsenic — some artists got sick from their own materials.
Salvador Dali carried a bell in his pocket and rang it when he felt a lack of attention. He considered himself a “living masterpiece” and behaved like a work of art.
During the Second World War, many masterpieces were hidden in the Alps. Art became the targets of bombings, and at the same time — an object of protection, preservation, and resistance. During the full-scale war in Ukraine, museum workers, artists and volunteers literally save cultural heritage under bullets.
International Biomedical Laboratory Day
This is a professional holiday dedicated to laboratory assistants, biomedical analysts, technicians and all specialists who work behind the scenes of medicine and ensure accurate diagnosis of diseases. It is their work that allows doctors to make the correct diagnosis and prescribe effective treatment. And although patients almost never see these specialists, 70-80% of all medical decisions are made on the basis of laboratory tests.
The idea of establishing this day is connected with the name of Christian Burge, a Danish biochemist and doctor who was born on April 15, 1782. It was he who in the 19th century initiated the practice of clinical laboratory analysis of urine as a diagnostic method, which became an important step towards modern laboratory medicine. It was in his honor that the date of the holiday was chosen, which in many countries is officially recognized as a day of honoring biomedical workers.
This professional holiday has been celebrated since the 1990s in a number of European countries, and in recent years it has gradually gained recognition in other parts of the world, including Ukraine.
Biomedical laboratory specialists are highly qualified specialists who work in clinical diagnostic, microbiological, biochemical, immunological, molecular genetic, PCR laboratories and other types of laboratories. They conduct complex studies of blood, urine, mucus, tissues, DNA, viruses, bacteria, tumor markers — everything that can give an idea of the state of the human body.
These specialists must thoroughly know the methods of analysis, the principles of operation of complex equipment, the rules of biosafety and laboratory sterility. They do not work with patients directly, but their work is critically important — without accurate analysis, treatment will be blind.
In the context of the war in Ukraine, biomedical laboratories became important for diagnosing infections among military and civilians, for preserving blood banks, monitoring the condition of patients in field hospitals, and analyzing chemical environmental pollution.
Interesting facts
More than 70% of medical decisions in the world are made on the basis of laboratory tests. From blood composition to PCR — each analysis is the basis for a clinical decision.
The world’s fastest laboratory test for COVID-19 was developed in the US — it gave a result in 5 minutes using isothermal DNA amplification methods.
A biomedical laboratory is not only about analyses. Medicines are tested here, genetic diseases are studied, tumor cells are analyzed, and personalized treatment protocols are created.
Robots work in modern laboratories. Automated systems for sample preparation, analysis, and output minimize human error and speed up processing.
There are more than 4,000 biomedical laboratories in Ukraine, most of which are private, but state laboratories remain key in the system of epidemiological protection.
A medical laboratory assistant or biomedical analyst in Ukraine receives one of the lowest salaries in the medical field, despite the fact that his work is difficult, responsible and requires higher education and certification.
International Day of Microvolunteering
This is a little-known, but very modern and important holiday dedicated to a new format of volunteerism that allows each person to help others even for a few minutes a day. This day is a reminder that doing good doesn’t necessarily require a lot of time, money or special skills — sometimes it’s just a matter of pressing a button, writing a letter, translating a text or spreading the truth online. The holiday is held under the slogan: “All great things begin with small things.”
Microvolunteering is help that can be provided online, quickly, without commitment and without long-term involvement. It can be 5 minutes of free time on the phone, in transport or during a break between work – time when a person does something useful for society: answering requests for charity projects, helping machine learning, training neural networks, editing maps for emergency services, translating, reading texts for the blind or checking facts. This concept emerged in the early 2000s along with the development of the Internet and mobile applications. It is gaining particular popularity in a world where many people want to help but don’t have time for traditional volunteering.
The holiday was started by the organization Help From Home from Great Britain, which popularizes the idea of microvolunteering. It was this platform in 2008 that began collecting projects in which anyone can join a useful cause in a few minutes — without leaving home. In 2014, April 15 was marked for the first time as a day to honor microvolunteers around the world.
Interesting facts
The best-known example of microvolunteering is the Zooniverse project, where users help scientists classify images from telescopes, microscopes or safari cameras to accelerate scientific discoveries.
In 2015, more than 1 million people around the world participated in micro-volunteering actions from the comfort of their homes, with an average participation time of 5-10 minutes.
In 2022-2023, Ukrainian IT volunteers massively joined micro-volunteering, helping with translations, information verification, checking photos from the scene of events, and even helping with OSINT investigations.
In some countries, micro-volunteering counts as volunteer experience in a CV or portfolio – especially for young people who want to prove their social activism.
Thanks to microvolunteers, tens of thousands of ancient manuscripts have been deciphered, new species of animals have been found, and thousands of missing people have been identified.
Historical events on this day
1657 – an important political event took place in the city of Chigyrin: the Cossack Council officially approved the transfer of the hetman’s mace from Bohdan Khmelnytskyi to his son Yuriy. This became the first precedent of the inheritance of hetman power in the Cossack state, which testified to an attempt at dynastic stabilization after the difficult war years.
1729 – the premiere of one of Johann Sebastian Bach’s most profound works – the oratorio “Matthew Passion” – was played on the music stage of Leipzig. This monumental work became a symbol of Protestant spirituality, the complexity of the composition and incredible emotional power.
1861 – the first session of the Galician Seim, the autonomous parliament within the borders of Austria-Hungary, began its work in Lviv. This was an important step for the Ukrainians of Galicia in the struggle for national representation and language, although Polish interests dominated it.
1874 – in Paris, on the Boulevard Capucins, a group of artists who were not recognized by the official academies opened their own exhibition. Claude Monet, Pierre-Auguste Renoir, Camille Pissarro, Paul Cézanne and Edgar Degas started a new era – Impressionism, which forever changed the course of the history of painting.
1893 – Ukrainian singer Solomiya Krushelnytska first appeared on the professional opera stage in Lviv in the role of Leonora in Gaetano Donizetti’s “The Favorite”. Later, she became one of the most famous opera divas in the world.
1920 – during the 1st Winter Campaign of the UNR army, the legendary black Zaporizhia under the command of Petro Dyachenko captured the important railway station of Voznesensk. It became a tactical success in the fight against the Bolsheviks and a symbol of the heroic mobility of the UNR army.
1940 – a neutrality pact was signed between the USSR and the Japanese Empire. In addition, the parties recognized the inviolability of the borders between the Mongolian People’s Republic (an ally of the USSR) and the state of Manchukuo (a satellite of Japan), cementing the balance of power on the Far Eastern front.
1943 – the countries of the anti-Hitler coalition created a unified command of naval operations in the Mediterranean Sea. This decision made it possible to more effectively coordinate the actions of the allied fleet, especially in preparation for the landing in Italy.
1948 – the first large-scale armed conflict occurred between Israelis and Arabs, which preceded the war for Israel’s independence. This event opened a new era of conflicts in the Middle East, which continues to this day.
1950 – the Ministry of Internal Affairs of the USSR issued an order on the indefinite resettlement of members of the OUN who were deported from the territory of Western Ukraine. This officially established the policy of repression and forced rejection of the Ukrainian liberation movement from its native land.
1952 – the first flight of the Boeing B-52 Stratofortress heavy strategic bomber took place. This aircraft became a symbol of American military power during the Cold War and remains in service in the 21st century.
1989 – at the Hillsborough Stadium in Sheffield, during a football match between Liverpool and Nottingham Forest, 96 fans died and more than 700 were injured in a stampede. This tragedy was a turning point in changing the safety rules at sports arenas in Great Britain.
1993 – in Turkmenistan, President Saparmurat Niyazov officially announced the transition from the Cyrillic to the Latin alphabet for the Turkmen language. This move was part of the policy of “national revival” and distancing from the Soviet heritage.
1994 – Ukraine joined the Economic Union of the CIS countries as an associate member. This decision reflected Kyiv’s complex political maneuvering in the face of post-Soviet instability and the desire to preserve trade ties without the ultimate loss of sovereignty.
2019 – a large-scale fire broke out in the Notre-Dame Cathedral in Paris. A blaze destroyed the roof and spire of one of Europe’s most famous Gothic shrines, sparking an outpouring of grief and fundraising for restoration. The cathedral became a symbol not only of religion, but also of the historical memory of mankind.
Birthday Leonardo da Vinci
On April 15, 1452, in the small Tuscan village of Anchiano near the town of Vinci, Leonardo da Vinci was born – a great Italian, an amazing person, a talented artist and inventor engineer, a sculptor, an outstanding architect, a clever writer, a philosopher, a fine musician and a meticulous anatomist. His birth was not accompanied by any honors or predictions of fame: he was the illegitimate child of the notary Sir Piero da Vinci and the peasant woman Catherine. The lack of noble origin and official status at an early age did not prevent him from becoming one of the key figures in the cultural history of Europe.
As a child, Leonardo lived with his mother, and later in his father’s house, where he received his primary education. He did not study Latin systematically, which became an obstacle to a deeper acquaintance with ancient texts, but this did not prevent him from independently mastering anatomy, mechanics, optics, botany, architecture and other fields of knowledge. His natural curiosity and phenomenal observation formed a unique approach to learning about the world, based on continuous research, drawing, sketches and experiments.
In the 1470s, Leonardo entered the workshop of Andrea del Verrocchio in Florence – it was there that he began to combine painting with technical thinking. Already in his first paintings – such as “Annunciation” or “Madonna with a flower” – attention to details, construction of space, transmission of light, which will later become defining features of his style, can be felt.
Working at the courts of various patrons – in Milan, Florence, Rome and France – Leonardo was not limited to art. He designed military vehicles, explored river systems, designed fortresses, created anatomical atlases, wrote treatises on painting and proportions. His diaries, written in a mirror style with his left hand, contain thousands of drawings, sketches and notes, indicating a remarkably wide range of interests.
Interesting facts
Leonardo wrote from left to right, in a mirror style, which makes it difficult to read his notes. Scholars still do not agree whether this was done for secrecy or as a convenience for left-handed people.
He dissected the bodies of people and animals, creating one of the first anatomical atlases in history. It contains precise descriptions of muscles, nerves, blood vessels, the skeleton, and internal organs—a level of knowledge that medicine would achieve only centuries later.
In his records you can find prototype drawings of a helicopter, a parachute, a submarine, a ball bearing, a tank, and even an automatic crossbow mount.
He did not complete most of his paintings. To his contemporaries, this seemed careless, but he often simply lost interest or did not consider the work completed due to technical experiments that did not give the expected result.
Leonardo worked for a long time on the image of the “Mona Lisa” – he kept this picture with him until his death and constantly changed it. Research shows that several versions of the portrait are hidden under a layer of paint.
He was interested in facial expressions, emotions, physiognomy. His portraits often contain remarkably accurate observations of facial muscle movement and bodily plasticity, which was rare for the era.
Leonardo spent the last years of his life in France at the court of Francis I, where he died on May 2, 1519, in the estate of Clos Luce. The king treated him as a sage, not just an artist.
The life of Leonardo da Vinci is an example of extraordinary work on himself, constant observation of the world and critical thinking. He did not belong to any school, did not adhere to canons, and did not seek to systematize knowledge within a narrow discipline. On the contrary, he looked for connections between seemingly unrelated things. And thanks to this, he became what he is still remembered for.
