Patomskiy Crater

The Patomskiy Crater (also called the "Fire Eagle Nest" by local Evenki people) was first reported to Soviet scientists in 1949 by a geologist who stumbled upon it while surveying for mica deposits in the remote taiga of Irkutsk Oblast, Siberia — one of the least accessible regions in Russia, reachable only by a multi-day trek through dense forest. The formation is a cone of crushed and broken limestone roughly 160 metres in diameter and 40 metres high, with a smaller mound at its centre, sitting incongruously on a forested hillside with no other unusual geology nearby.

No crater of comparable form, age, or composition is known anywhere else in the world, and despite numerous expeditions since the 1960s, no definitive explanation has been established: proposed origins include a meteorite or comet impact (no meteoritic material has been conclusively identified at the site), a deep-seated gas or steam explosion, and even — among more speculative proposals — an unexploded underground nuclear-type event. Radiocarbon dating of trees disturbed by the formation's creation suggests it formed within the last few hundred years, which if accurate would make it remarkably young for a feature of its size and would mean the event that created it was potentially observable, yet no historical record of it has been found. The local Evenki population has long avoided the site, regarding it as cursed ground associated with unexplained deaths of animals and, in older accounts, people who approached it.