• Two open playgrounds at Veliki and Mali Kalemegdan, plus a Dino park and the Belgrade Zoo on the grounds
• Paid sites close Mondays, and Nebojša Tower on Tuesdays too, so save the towers and bunker for later in the week
• Medieval torture devices fill the Casemates exhibit, which can be too grim for younger kids

Belgrade Fortress sits on a ridge where the Sava meets the Danube, with Kalemegdan Park wrapped around its walls. Kids can walk the ramparts and old gates, find the Victor monument and the fortress cannon, and go down into the Roman Well, a military bunker or the Nebojša Tower.

The park side has two open playgrounds, a Dino park and the Belgrade Zoo, plus basketball and tennis courts.