Visit the Erbil Citadel

Red-sandstone castle ruin above the old town of Heidelberg and the Neckar valley.

Belarus’s best-preserved historic centre, with two castles above the Neman.

The "museum without walls": grassy royal burial mounds, the Cheomseongdae observatory and Silla-dynasty treasures across the town.

Moorish palace-fortress of Granada.

Renaissance sea fortress at Helsingor — the Elsinore of Shakespeare’s Hamlet.

One of Europe’s largest castle ruins, sprawled across a travertine hill.

16th-century castle, UNESCO-listed.

Renaissance Radziwill palace and park.