The Phrygians lived in this part of the central plateau of Anatolia (now Turkey) in the first millenium BC, before Greek & Roman culture took hold in the area. They built rock-cut tombs, of which this is the remains of one. To visit most of the Phrygian sites, you need a good guidebook and a willingness to get lost repeatedly down poorly-signposted little dirt roads (but that just adds to the fun).