The ghost town of Kayaköy itself, including hundreds of abandoned houses with no roofs or windows, and the walls of some of which are partially ruined, is the main sight. Those not to be missed include the old fountain which dates back to 1888 by the tarmac road, two abandoned churches aptly dubbed Yukarı Kilise and AÅaÄı Kilise, i.e. "Upper" and "Lower Church", respectively, because of their relative elevation difference to each other, and the little chapel on the top of the hill about 20 min uphill walk from the lower church; follow the red dots from the church, which gives a stunning view of the valley and the sea below, which are located on the other side of the hill that Kayaköy leans against, and therefore is not visible from the town itself.
The lower church and the streets or stairs to be more precisely in its vicinity has been declared a "museum" by the Turkish Ministry of Culture with a ticket office in the entrance which require anyone passing through—whether they have the intention to check out the church or not—to buy a ticket which costs 8 TL pp. You may pass on the early and late hours of the day on which the office is unmanned without buying a ticket, though.
afkule and gemile
8 km southwest of Kayaköy, the beach at Gemile is accessible by a gravel road good enough for most conventional cars from the neighbourhood of Kınalı, about 2 km west of the ghost town, although there is no public transport heading there. There is also a hiking path which somewhat shortcuts the gravel road. The trail begins out of Kınalı, at where the road starts windings and descents towards the coast. Just off shore of Gemile is the St Nicholas Island Gemiler Adası in Turkish with some ruins of a Byzantine chapel which dates back to 5th century.
Perhaps a more rewarding sight in the same direction is the monastery at Afkule also spelled Af Kule, clinging at the high cliffs over the sea, and which affords really impressive views over the Gulf of Fethiye, as far away as Rhodes if the air is clear. Other than its roof, this Greek Orthodox monastery is as sound as it was when abandoned in 1920s. To get there, you will need a short about 3 km but pretty demanding hike up and down along a trail, part of it, though, fortunately, through a pine forest. In total it takes around an hour on foot to get there from the ghost town. West of Kayaköy, leave the gravel road to Gemile at where the trail a dirt track to Afkule branches off, which is properly marked by yellow signs. At about midway through the trail to Afkule about 1 km away from where you started, you'll notice a branching track to right—this is the wrong path, keep to the trail to left instead. The trail ends in a open space—carpark for those taking their vehicles along the track. From here, take the wide track to right, which is waymarked with the yellow&red marks usual in the area, and which will slowly ascent to the top of the cliff, which is about 1 km away from the carpark. Then the trail will descend down to the monastery, but be extremely careful in this section as it is very easy to slip down since the path is covered with loose gravel. Perhaps not for the faint hearted, you can further explore the lower stories of the complex the church and residences of the monks once you are in the monastery, though that will require a very steep climb down with the full view of high cliffs down to the coast a whopping 400 mt just below your feet, so those with afraid of heights—do beware.