Some ramparts and walls still survive on the steep cliff that is the site of Bursa's citadel and its oldest neighbourhood, Tophane. Walk up Orhan Gazi (Yiğitler) Caddesi to reach the hisar (fortress). On the summit, a park contains the Tombs of Sultans Osman & Orhan, the Ottoman Empire's founders. Osman Gazi's tomb is the more richly decorated.
Although it was ruined in the 1855 earthquake, Sultan Abdül Aziz rebuilt the mausoleum in baroque style in 1863.
The six-storey clock tower, the last of four that also served as fire alarms, stands in a square with a cafe where families and couples gaze out over the valley and snap photos.