Batagaika crater
The Batagaika crater is a thermokarst depression in the Chersky Range area. The biggest permafrost crater in the world, it administratively belongs to the Sakha Republic Russia and is in its Verkhoyansky District. Description. The depression is in the form of a one-kilometre-long gash up to 100 metres (328 feet) deep, and growing, in the East Siberian taiga, located southeast of Batagay and northeast of the settlement Ese-Khayya, about north-northeast of the capital Yakutsk. The structure is named after the near-flowing Batagayka, a right tributary of the river Yana. The land began to  sink due to the thawing permafrost in the 1960s after the surrounding forest was cleared. Flooding also contributed to the enlargement of the crater. Paleontologists have found Ice Age fossils buried in the mud around the rim of the crater. The rim is extremely unstable as there are regular landslides into the crater and the permafrost is constantly thawing. The crater is currently growing in size. According to Mary Edwards of the University of Southampton, the process of erosion that increases the crater's size occurs in the following way:"Below the cliff face, steep hills and gullies drop to Batagaika 's floor. As more of the material at the bottom of the slope melts and comes loose, a larger face is exposed to the air, which in turn increases the speed of permafrost thawing. The crater will likely eat through the entire hillslope before it slows down. Every year as soon as temperatures go above freezing, it's going to start happening again. Once you've exposed something like this, it's very hard to stop it".According to research published in 2016, the crater wall has been growing by a yearly average of 10 meters per year over a  ten-year observational period. Fossils. The rapid expansion of the crater is uncovering a host of fossilized materials, including ancient forests and pollen and animal carcasses such as that of musk ox, mammoth and horse, along with other animals. It also allows for insight into 200,000 to 650,000 years of climate data.