Sighisoara Citadel is the inhabited medieval upper town, a 12th-century Saxon fortified settlement and UNESCO World Heritage Site. Its lanes, towers, churches, and coloured houses make it the main reason to come to Sighisoara rather than just pass through.
Start with the Clock Tower and then walk the walls, guild towers, Scholars' Stairs, and streets around the central square. The citadel is compact, but it rewards slow wandering.