Tomb carved into sandstone rock of Jabal Banat (Qasr Al-Bint) area in site of Hegra (Madain Salih), UNESCO, AlUla, Medina Province, Saudi Arabia

Tomb carved into sandstone rock of Jabal Banat (Qasr Al-Bint) area in site of Hegra (Madain Salih), UNESCO, AlUla, Medina Province, Saudi Arabia

Tombs carved into sandstone rock of Jabal Banat (Qasr Al-Bint) area in site of Hegra (Madain Salih), UNESCO, AlUla, Medina Province, Saudi Arabia

Tomb of Lihyan, son of Kuza (Qasr al-Farid), carved into sandstone outcrop within the Site of Hegra, UNESCO, AlUla, Medina Province, Saudi Arabia

Woman at Tomb of Lihyan, son of Kuza (Qasr al-Farid), carved into sandstone outcrop in Hegra, UNESCO, AlUla, Medina Province, Saudi Arabia

Remarkable sandstone rock carved by erosion in the Ashar Valley, AlUla, Medina Province, Saudi Arabia

Tse Bighanilini Slot Canyon (Upper Antelope Canyon), carved sandstone formations, Antelope Canyon, Arizona, United States of America, North America

Tse Bighanilini Slot Canyon (Upper Antelope Canyon), carved sandstone formations, Antelope Canyon, Arizona, United States of America, North America

Close-up of coloured sandstone from which the Nabateans carved their city, Petra, Jordan, Middle East