Castles, palaces and monuments — hidden gems

In Cairo, behind the Mosque of Sultan Hassan, a circular wooden hall where the Mevlevi dervishes danced: the Mevlevi Museum.

In Williamsburg, a civic museum in a storefront window: dentures from Dead Horse Bay, World's Fair memorabilia, and a shrine to Jackie Robinson.

In Marrakech, next to the Ben Youssef Mosque, the Almoravid Koubba: the only surviving Almoravid building in Marrakech, rediscovered in 1948.

The mausoleum of the dervish Gül Baba in Budapest: a sixteenth-century Ottoman tomb on the Rózsadomb, free to enter and hushed among the roses.

Beneath Copenhagen's Søndermarken park, a former water reservoir hides a cavernous underground gallery of contemporary art, unknown to most visitors.

In the free park of Karlberg Palace, in Stockholm, lie the grave of Charles XII's dog, the Temple of Diana and a runestone.

In Dublin a London plane tree has swallowed a cast-iron bench: the Hungry Tree in the grounds of King's Inns, a quiet botanical curiosity.

A free museum in Meguro, Tokyo, devoted solely to parasites: 300 specimens and the longest tapeworm in the world, 8.8 metres.

Beyond Arashiyama, in Kyoto, a hillside temple with 1,200 rakan statues in the moss: each face is different, carved by amateur devotees.