The silly symbol for an underground protest group is now scattered around the city.

An underground city of salt.

The walls and ceiling of this Polish church are decorated with thousands of skulls, with another 21,000 skeletons just below.

This automated sculpture of two men peeing will spell out text messages with their micturition.

The mystery of the Putim Ossuary involves a tricorn hat.

A church of bones, decorated with 40,000 human skeletons.

An enormous and lavish Gothic church in Czechia.

Despite attempts by local police to discourage it, Beatles-inspired graffiti has been a means for artists to air grievances for decades.

Macabre astrological automaton clock dating to the late 1400s.

Early habitat dioramas and home of the elusive gaff, the skvader.

It houses the remains of a 17th-century version of the Titanic.

Sweden's oldest animated sign is still lighting up the skyline today.

Stockholm's decidedly unique public transit system has doubled as the world's longest art gallery for decades.

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

Charles Dickens was not a fan of the ghastly wall dressings in this 6th century church.

A sculpture serving as an homage to Pope John Paul II.

Museum dedicated to literary greats of the Romantic Period is also the home in which Keats met his untimely end.

There aren't too many operational funiculars around, but Pittsburgh has two!

A favorite with sightseers and locals alike, this Norwegian funicular provides easy access to a stunning view of Bergen and its environs.

The water-powered carriages are long gone, but for over a century this funicular railway has been the fastest route to the highest point in Paris.

On the Oregon coast is a natural hole that seems to be draining the sea.

The earliest known map to show America, discovered by accident at a Paris bookshop.

An impressive monument to Poland's independence.

Museum dedicated to "the man who moved the Earth."