This ornate Victorian marketplace was the setting for Diagon Alley and the Leaky Cauldron in the Harry Potter films.

This 1920s Dutch barge is now a floating bookstore.

A subterranean ice warehouse that has lain hidden beneath central London for over a century is now open to the public.

A labyrinth hides in plain sight at each of the city's 270 Tube stations.

The unusual lighthouse looms over waves of prairies with no sea in sight.

Underground tunnels once home to crime are now back open to the public.

A southern Swedish island is home to the last ERSTA artillery battery, meant to protect the shoreline during the Cold War.

Rocks carved with biblical passages in the 1800s.

A former top secret military tunnel is now stuffed with snow and open year-round to skiers.

The official meeting point for the oddly named governing assembly of ancient Sweden.

Uppsala's adorable feline sign celebrates a popular children's book set in the Swedish city.

Archaeologists are still unraveling the secrets of the brutal massacre that wiped out this ancient fort.

The concrete skeletons of an abandoned Swedish town hide among the trees.

This homeless brass fox tugs at your heartstrings from the foot of a Stockholm bridge.

Bring your hiking shoes, wool socks, and thermal underwear for a stay in these cozy forest huts.

A water reservoir disguised as a castle stands atop a hill in a park in Stockholm city.

Outside a Viking museum sits a modern-day runestone made by a Swedish runemaster using traditional methods.

The suspected burial mound of legendary Viking Björn Ironside.

A plaque marks the house in Stockholm where the French philosopher René Descartes lived up until his death.

No one knows who's responsible for decorating this tunnel with stuffed animals, but the people love it enough to protest their removal.

This grisly exhibit houses skeletons and weapons from a devastating 14th-century clash.

Sweden's "good old days" painstakingly re-created in a model village.

An ancient Viking runestone hidden in plain view in Stockholm's old town.

Stockholm's deepest subway station is also a stunning ecological wonder.