The first, and perhaps only, monument dedicated to Wikipedia.

Special benches that play Chopin's music are scattered throughout his native city.

This 13th century Gothic brick castle is the largest in the world by surface area.

Poland's oldest salt mine has nearly everything one needs to live underground forever.

A haunting deserted hotel is a favorite with artists and photographers.

An abandoned Nazi explosives plant founded by the inventor of dynamite is now an underground museum.

St. Mary's features one of the most spectacularly decorated cathedral interiors in all of Europe.

A program of Communist glamour in post-Stalin Poland is preserved in this colorful museum.

This uber-quaint Polish village is known for its habit of painting elaborate floral motifs on just about everything.

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.

The dining hall that nourishes workers in Chernobyl's Exclusion Zone is also open to visitors.

A fortress built to pacify local uprising that had a stint as a Nazi concentration camp before becoming a five-star hotel.

One of the world’s best microminiaturist, Nicolaï Siadristy displays his lifetime of tiny creations in this museum.

A subterranean Holocaust refuge within one of the world's longest cave systems.

The largest catacomb system in the world.

This attraction was abandoned after the Chernobyl disaster.

The ghost town left by the worst nuclear disaster of all time is being taken over by nature and urban explorers.

A mysterious "wedding cake" castle in the middle of the urban desert.

Open since 1938, this diner has kept its fountain, malt machine, and all the gum that greasers left beneath its counter.

The installation’s official name, “You Who Are Getting Obliterated in the Dancing Swarm of Fireflies,” says it all.

Remants of foundations, streets, and streetcar tracks inhabit the cliffs where a landslide occurred in 1929.

Wondrous sandstone hoodoos where Native Americans collected clay for pottery, 9,000 years ago.

This secluded aqua waterfall in the Grand Canyon is the perfect swimming hole, and the Havasupai tribe's fiercely protected natural wonder.