The Batagay megaslump (also called the Batagaika crater) is a large pit in Siberia. It is caused by the permafrost melting. This megaslump began as a cut on the side of a hill. It is the largest megaslump in the world. Scientists are interested in the Batagay because it has a natural record of past ecology. Remains of extinct animals such as the prehistoric steppe bison and cave lion have been recovered.