No need to strap in for a "ride" on this walkable roller coaster.

The birthplace of Karl Marx is now a museum dedicated to the communist revolutionary's life and work.

The last bastion of Roman presence north of the Alps looms over a German town.

The oldest Jewish cemetery in Europe survived Hitler's Germany.

This 600-year-old home seems to defy physics.

This medieval castle overlooking the Elzbach river looks just like it did hundreds of years ago.

This 19th-century convent is now a flourishing 21st-century hub for art.

This strange portrayal of the state's first lieutenant-governor literally stands on its head.

This Australian beach became famous when Prime Minister Harold Holt disappeared from its shores.

People can't get enough of these adorable Japanese photobooths.

Built over an abandoned train yard, this hidden gem is full of winding paths and offers gorgeous views of Sydney Harbour.

A simple tribute to the migrant workers who landed here before walking hundreds of miles to Victoria's gold mines.

You can climb to the top of the world's largest rocking horse.

It's home to the antenna that received the first images of Neil Armstrong walking on the moon.

You'll find the little birds tucked within the rocks of this Australian beach.

The labyrinthine storm tunnels beneath the city of Melbourne are ruled by a band of urban explorers.

Occult books, tarot, oddities.

A beautiful 1920s tower filled with local hidden gems.

Tiny artwork tucked within glass letterboxes form this hidden gem of an art gallery.

Dancing skeletal figures pay homage to a medieval mural destroyed during World War II.

Hopefully inspecting his tin pan for little nuggets of gold.

Tiny memorials honor individual victims of the Holocaust.

The slender brass strip in Prague's Old Town Square was used to tell time from 1652 to 1918.

This giant Christ statue was a failed attempt by Indonesia to dissuade East Timor from demanding independence.