I wasn’t planning on posting this picture, but I decided that the interior of the diwan and the work on it were pretty amazing.
“The diwan (meeting room), carved into a hillside to shield it from the wind, is one of the few extant examples of non-funerary architecture in Mada’in Saleh. … [The area was probably used by the Nabataeans] as a cult site. Opposite the hollowed-out room are niches cut into the rock where Nabataean deities were carved – now sadly weathered.” (from Lonely Planet, “Oman, UAE & Arabian Peninsula”)
This is the very impressive exterior of the diwan: