The curious underground history of keeping Paris clean.

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

The bears of Bern have been a city highlight for over 500 years.

A cablecar-station-turned-revolving restaurant with 360-degree views of the Swiss skyline.

A nearly 500-year-old sculpture depicts a man eating a sack of babies, and no one is sure why.

Years of neglect and nature took a toll on this 19th-century lighthouse.

The bat-covered home of one of the world's most popular brands of rum is located on a tropical Art Deco campus.

The world's second largest single-dish radio telescope, once used to contact E.T.

A roaring, awe-inspiring double cascade of icy water flows through woodland Oregon like something out of a Tolkien novel.

A museum dedicated to the history and exploration of both popular music and science fiction.

A walk through the historic city center, under the streets of Seattle.

The first American home of the isolated, egalitarian religion has a trove of Shaker architecture and artifacts.

The unique waterfall in Iceland's south features a backdrop of geometric black lava columns.

A sulfuric martian landscape that looks far better than it smells.

A charmingly eccentric magma chaser presents his complete history of the island's eruptions since 1947, in cinematic form, just for you.

One of the tallest buildings in Iceland, and perhaps, the most visually impressive.

This Netherlands museum holds a gloriously mechanical collection of ornate musical automata.

Cat art as far as the eye can see.

This city square is home to Amsterdam's oldest church and a statue honoring Dutch sex workers.

A hugely vast Irish landscape of barren rock that stretches for miles.

The most iconic structure in Scotland has been home to bishops, colonels, and Sean Connery characters.

A 1,215-foot tunnel transports pedestrians beneath the River Thames.

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

Pop culture has helped to keep this iconic British building from being destroyed.