Watch new footage of the mysterious giant hole that opened up in Siberia as a scientific expedition — with the country’s Emergencies Ministry represented — reaches the remote site and looks inside. An explosion below the ground is currently thought to be the most probable explanation — but the date and cause remain unknown.

The hole sits around 2900km east of Moscow in a huge 640km stretch of permafrost with a wide variety of animal species and that is famous for archaeological discoveries including wooly mammoths. The zone is also of key strategic importance for Russian oil and gas production.

A 70cm layer of permafrost reportedly discovered around the edge of the hole — mentioned in the video — is puzzling given the amount of heat that would be expected to have been generated by an explosion of the magnitude necessary to create such a large crater. It is therefore possible that the remote site lay undiscovered for months if not years.

Members of the Russian Academy of Sciences are on the expedition and are said to be collecting samples of soil, air and water from the area. The hole reportedly has an outer diameter of around 60m and an inner diameter of around 40m. The depth is unconfirmed.