In a few kilometers from the ruins of Hattushash (the ancient capital of the Hittites) located Yazilikaya sanctuary. It was used by the last Hittite kings. Was discovered in 1838 by French archaeologist and traveler Charles Felix Texier.
The oldest parts of the sanctuary dated back to 15th century BC. But all the main inscriptions appeared about 1250-1220 years BC. Currently Yazilikaya looks like some huge stones-rocks, but the place itself is beautiful.
Walls of the sanctuary store very valuable data. For example the full pantheon of gods that period and inscriptions done with Hittite (Luwian) characters. This disappeared language was found even in Troy, though it is located a thousand kilometer away, outside the Hittite Kingdom. In 1952-69 French linguist Emmanuel Laroche managed to decode most of the characters and inscriptions in Yazilikaya.

Rock carving in Chamber B depicting god Sharruma and King Tudhaliya dated to around 1250 - 1220 BC ©AtilimGunesBaydin / wikipedia.org
Getting there: Check how to get to Hattushash.