The Batagaika Crater (near Batagaika river, by a town named Batagai in the Verkhoyansky region of Siberia) started forming about 25 years ago but rapidly increased in size after local flooding in 2008. It's now about 1,500m long and over 120m deep in places (and growing at about 20m per annum as the permafront warms). The initial formation was due to uncontrolled deforrestation in the early 1990s for an industrial facility but subsequent warming of the glacial soil has caused the crater to continue growing. While an interesting (and somewhat frightening) phenomena and a warning of the effects to come from global climate change the crater is also a fascinating opportunity for paleogeologists, providing a glimpse into the history of Siberia as it was 200,000 years ago. Exploration of the crater (or 'megaslump' to geologists) has yielded the remains of bisoin, musk ox, reindeer, mammoths and a Holocene-era horse.