I visited this WHS in Spring 2021. Bogazkale is a perfect stopover point in Curum between Safranbolu and Goreme NP. Even though the WHS is made up of 4 locations, the Kayali Bogaz (outpost) and the Osmankayasi (rock necropolis) are perfectly visible from in and around Hattusha and Yazilikaya and are minor sites when compared to the massive Hattusha site and the impressive engravings of Yazilikaya. The entrance ticket to Yazilikaya is included with the ticket to Hattusha and really shouldn't be missed (even if you're pressed for time, it won't take longer than 15-30 minutes and you won't regret it).

Yazilikaya literally means "inscribed rock" and it includes some of the most important rock reliefs of the Hittite Empire. The best time to visit is probably in the early morning unless you manage to organise a night visit with a torch! Yazilikaya was a sanctuary for the Hittites and as much as 64 deities are depicted in the foundations of what were once Chambers A and B of this Hittite "pantheon". Along Chamber A the main highlight is the procession of male mountain gods wearing the traditional kilts, pointed shoes and horned hats, while along Chamber B the fewer rock reliefs are much larger and better preserved and it may have served as a mortuary mausoleum or memorial. The winged solar and lunar deities are strikingly reminiscent of Egyptian hieroglyphics.

Hattusha on the other hand is really a fully blown razed city which requires at least half a day to visit, especially if you visit on foot (think 7-10 km uphill under the scorching sun with nowhere to shelter for some shade. The site is so large that a very well organised loop for vehicles circles the entire main area and you're allowed to access the site by car and park at the different highlight spots. Being mostly in ruins not much is left in most sites but the remaining foundations and reconstructed entrance gates give you an idea of the imposing scale and size this site once had. Definitely do not miss Lions' Gate, Sphinx Gate (the originals are worth viewing in the very worthwhile Bogazkale Museum with a separate ticket) and Yerkale "rampart", King's Gate and the unknown warrior sculpture, the Great Temple with the excavated pottery and green cubed stone, Nisantepe (a giant 8.5 metre rock with Luwian hieroglyphics) and last but not least the Hieroglyph Chamber (with the impressive embossed sun god and six-line epigraph).

All in all, this is a really top WHS covering a great ancient empire. There are UNESCO inscription signs just before the entrances to both Yazilikaya and Hattusha. A visit to the Bogazkale Museum is a great way to add context to your visit (there's also the UNESCO inscription certificate inside).