Rock-cut Tombs of the Pontic kings (Amasya, Turkey)
Those royal tombs date from about 300 BC to 200 BC. They are carved in a vertical cliff above the city of Amasya, which used to be the capital of the Kingdom of Pontos.
For more information about those rock-cut tombs, read en.wikipedia.org/wiki/Tombs_of_the_kings_of_Pontus.