Patomskiy crater or Patom crater (Russian: Патомский кратер, (Patomskiy Krater), also known as Конус Колпакова, Konus Kolpakova "Kolpakov cone") or "Fire Eagle Nest"[1] is a peculiar rock formation located in a remote area in the Irkutsk region of southeastern Siberia, 360 kilometres (220 mi) from the district center Bodaibo.[2] It is a large mound made of shattered limestone blocks, rising from dense taiga. Its base diameter is about 160 metres (520 ft) and its height about 40 metres (130 ft); the cone's crown is ring-shaped, and in its center there is a smaller mound with a height of about 12 metres (39 ft). The volume of the crater is estimated as 230,000–250,000 cubic metres (8,100,000–8,800,000 cu ft), with a weight of about one million tons.

The Patomskiy crater was discovered in 1949 by Russian geologist Vadim Kolpakov. Its origins have been subject of intense scientific interest, with hypotheses including meteorite, volcanic and gaseous origin, but to date no definite proof has been given. It is estimated to be only 300 to 350 years old. Nearby trees seem to have experienced rapid growth that has been theorised to be caused by radiation.

Until recently, some scientists believed that the crater presents a large footprint of an ultra-dense meteorite, which had sunk underground upon impact. Another hypothesis was that it is a fragment of the Tunguska meteorite. Others believed that the crater is a result of a breakthrough of a deep pocket of natural gas. Several scientific expeditions have been sent to the crater but the nature of its origin remains a mystery.[2] Astronomers and geophysicists from the Irkutsk State Technical University, geochemists from the Institute of Geosphere Dynamics, RAS (Moscow), however, believe that the crater may still have a meteoric origin.