Rock-Tombs of the Pontic kings (Amasya, Turkey)
You can see the passage between the two tombs also on this photo.
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.