Heritage walk, Char Minar. They are organized by the AP tourism department and led by a knowledgeable guide and Tourist Police. There are two flavors of walks so far, one that ends at Chowmohalla palace, and the other that ends at Badshahi Ashoorkhana.Bonus - breakfast served too! It's probably better to call up at  beforehand and confirm which walk is on. Ticket price is Rs 50 per head and can be bought at char minar on the spot.