Geologist Day is observed on April 5 and is celebrated in Russia, Ukraine, Belarus, Kyrgyzstan, and Kazakhstan. This professional holiday was established in 1980 in the Soviet Union, following a request from prominent geologists, led by academician Alexander Yanshin, after the discovery of oil and gas deposits in the West Siberian province in 1966. The date marks the end of winter and the beginning of preparations for summer fieldwork. Geological and mining organizations traditionally celebrate this day, and it is recognized by others involved in related fields of geology. The holiday has persisted even after the collapse of the Soviet Union, highlighting its significance in the geological community.