Batagayka crater in Siberia, known as the “gateway to hell” by locals, is almost 1 kilometer in length and 86 meters in depth. 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. Archeologists 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 Batagayka crater is making noises too as it consumes large chunks of the area. The crater is currently growing in size and it will likely eat through the entire hill slope before it slows down. Frank Günther of the Alfred Wegener Institute in Potsdam, Germany, showed that over the past decade crater grew by an average of 10 meters per year.
By NASA Earth Observatory images by Jesse Allen, using Landsat data from the U.S. Geological Survey. – https://earthobservatory.nasa.gov/IOTD/view.php?id=90104&src=eoa-iotd, Public Domain, Link