House on Fire Ruins, Anasazi Culture, over 800 years old, Mule Canyon, Cedar Mesa, Utah, United States of America, North America

House on Fire Ruins, Anasazi Culture, over 800 years old, Mule Canyon, Cedar Mesa, Utah, United States of America, North America

Aerial of Sassi di Matera in fog, UNESCO World Heritage Site, Basilicata, Italy, Europe

Cave paintings between 4000 and 5000 years old, Gruta do Janelao, Peruacu, Minas Gerais state, Brazil, South America

A Somaliland soldier stands guard at the 5000 year-old cave paintings in Lass Geel caves, Somaliland, northern Somalia, Africa

Religion, ethiopia. Na’akuto la’ab church, 7 kms from lalibela, built in a cave. The priest showing some of the church’s treasures: an old painting, gondar style

A man exploring the old abandoned Coniston copper mines in the Lake District, Cumbria, England, United Kingdom, Europe

Stalactite cave, Cuevas del Drach, Porto Christo, Majorca, Spain

Man climbing in a cave, Immenstadt, Bavaria, Germany

Woman and man relaxing in salt cave

A park ranger climbs a ladder to enter the Balcony House cliff dwelling at Mesa Verde National Park, featuring cliff dwellings of ancestral Puebloans that are nearly a thousand years old, Cortez, Colorado, USA

Gobabis Rock Art by the San Bushmen, Ghoha Hills or Bushman Hill, about 5,000 years old, Savuti, Chobe National Park, Chobe District, Botswana, Africa

Gobabis Rock Art by the San Bushmen, Ghoha Hills or Bushman Hill, about 5,000 years old, Savuti, Chobe National Park, Chobe District, Botswana, Africa

Cave painting from the stone age, Cheddar Man Museum of Prehistory, Cheddar, Somerset, England, United Kingdom, Europe

Cave paintings at Estancia La Maria, Argentina. They are between 4,500 and 13,000 years old.

Cave paintings at Estancia La Maria, Argentina. They are between 4,500 and 13,000 years old.

Bell Caves At Beit Guvrin, Israel

Bell Caves At Beit Guvrin, Israel

Upper falls hocking hills state park, Ohio united states of america