You can visit the old village on the top of the hill, lying like a ghost town on the feet of the castle. The village (an Unesco monument today) was populated till 1965, but some of the abandoned houses are already under reconstruction.
Then, you can climb up to the castle (built 800 years ago to protect the Halkians from the pirates of the Aegean Sea) for a journey back in time and a bird's eye view on the whole island, as well as the neighbor islands (Rhodes, Alimnia, Tilos and even Karpathos).
Every year on the 14th of August, a festival with traditional music and food takes place in honor of Panagia (Virgin Mary) who celebrates on August 15.