Kru­bera Cave, also known as Voronya Cave (Russ­ian for “Crow’s Cave”) is the deep­est known cave on Earth. It is locat­ed in the Ara­bi­ka Mas­sif, one of the largest high-moun­­tain lime­stone karst mas­sifs in the West­ern Cau­ca­sus region of Geor­gia. This moun­tain block con­tains sev­er­al hun­dred caves that start­ed to devel­op when the moun­tains start­ed to rise more than 5 mil­lion years ago.