This Industrial Age architectural and engineering gem helps visitors and residents alike traverse Lisbon, “The City of Seven Hills.”

The taxidermy remains of the first mammal ever cloned from an adult cell are on display in Edinburgh.

17th century streets hidden under Edinburgh were once a breeding ground for the black death.

Housing the famous Norwegian ice-defying 19th century polar exploration ship.

Home to three historic ships from the age of Vikings.

The "lost friend” is the most famous of the six moai statues that were removed from Easter Island.

These official units of measurement—including chains and perches—lie hidden beneath tourists' feet in a popular London hub.

After nearly 60 years, there's still a bear at Paddington Station looking for help.

Thanks to modern navigational tools we now know that the true prime meridian runs through a park next door.

This massive collection of British military artifacts includes the heartbreaking personal letters of the men in the trenches of WWI.

The television series' iconic giant foot was borrowed from this classical painting.

Hear the quietest sound from across the dome.

The perfectly preserved underground rooms where Churchill plotted the war against Germany.

Kings Cross Station pays tribute to its role in Britain's best-selling book series.

The iconic boulevard is the perfect place to catch sight of a bicycling skeleton, a levitating Satan, or a chef with his head stuck in a pizza.

Mountain where Jesus was first tempted by the Devil.

Gaudí's famously flamboyant architectural style is on full display in this sprawling park and garden.

One of Antoni Gaudí's most classic buildings is well-known for its "dragon-back" design.

Construction of Barcelona's iconic (but controversial) church is expected to be completed in 2026—a century after the death of its architect.

A scandalous Art Nouveau collaboration that set Paris all atwitter at the turn of the century.

The vast, legendary catacombs hold secrets much stranger than stacked bones.

One of the Seven Wonders of the Modern World holds the world's tallest metal staircase.

The mastermind behind this palatial hotel perished on the Titanic weeks before its grand opening.

Every year, the colorful murals of Montreal get a complete makeover.