Berber underground dwellings, Matmata, Tunisia, North Africa, Africa

Troglodyte pit home, Berber underground dwellings, Matmata, Tunisia, North Africa, Africa

Troglodyte pit home, Berber underground dwellings, Matmata, Tunisia, North Africa, Africa

Underground cave dwelling, Matmata, Tunisia, North Africa, Africa

Underground cave dwelling, Matmata, Tunisia, North Africa, Africa

Tourists visiting underground Troglodyte dwellings, Matmata, Tunisia, North Africa, Africa

Tourists exiting underground Troglodyte dwellings, Matmata, Tunisia, North Africa, Africa

Troglodyte cave dwellings Guadix

Ladder into an underground room, Kiwa, Spruce Tree House, a cliff dwelling of the Native American Indians, about 800 years old, Mesa Verde National Park, UNESCO World Heritage Site, Colorado, USA, North America

Ladder into an underground room, Kiwa, Spruce Tree House, a cliff dwelling of the Native American Indians, about 800 years old, Mesa Verde National Park, UNESCO World Heritage Site, Colorado, USA, North America

Stone and turf structure with wooden doorway at the recreated longhouse in Greenland's Brattahlid, Eriksfjord area, part of a reconstruction of Erik the Red's settlement, Kujataa World Heritage Site, Qassiarsuk, Southern Greenland, Greenland

Tunnels And Caves In The Kaymakli Underground City, Kaymakli, Turkey

Tunnels And Caves In The Kaymakli Underground City, Kaymakli, Turkey