A miniature train-ride through Slovenia's largest cave system.

The "dragon babies" of southeastern Europe.

The memorial stands at the intersection of the rivers Morava and Danube.

This spaceship sculpture in the middle of the Slovakian capital looks like it just crash-landed.

This Slovak bridge is known both for its connection to a national uprising and its UFO-shaped eatery.

Launched by Napoleon's soldiers more than 200 years ago, a cannonball remains embedded in the tower wall.

A statue marks the exact spot where The Boy Who Never Grows Up made his first literary appearance.

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

London's last remaining public soapbox site has seen speeches from Karl Marx, Vladmir Lenin, and George Orwell.

A unique tribute to the millions of animals who served and died for the British military.

A quiet, semi-secret square with statues of Mahatma Gandhi, Virginia Woolf, and a conscientious objectors stone.

This once-controversial and slightly confusing statue of Achilles was built out of captured cannons.

Once designed as the entrance to Buckingham Palace, this structure was later relocated and stands as a victory arch.

This long-hidden space above Westminster Abbey now displays the battle gear of the legendary King Henry V.

The bronze uniforms commemorate the vital role of women during World War II.

An easily overlooked stretch of ornate window fronts and gaslight lamps that could be right from the pages of Dickens.

A charming 17th-century alley is lined with secondhand bookstores and antiquarian shops.

Outside of one of Britain's most renowned social clubs, a step installed specifically for the Duke.

This coffee shop lies hidden beneath a historic church.

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

This towering church is home to a world-famous organ and a treasure trove of medieval art.

Tucked in the back of a flower shop, its collection details the fascinating history of the Netherlands's iconic symbol.

The former headquarters of history's oldest megacorporation.

High atop the Eiffel Tower is a small apartment built exclusively to entertain the science elite and make the rest of Paris jealous.