A towering spire in the fortress of Kalemegdan honors the victorious armies of Serbia during their struggles against the Ottoman Empire.

A musical instrument played by the sea.

The fairy tale castle of the "fairy-tale king."

Impossibly life-like natural history models created out of glass by a father and son.

The oldest museum in Russia is home to a fascinating collection of nearly two million anthropological artifacts and anatomical curiosities.

Macabre astrological automaton clock dating to the late 1400s.

The former home of the Nobel Prize-winning American writer is now home to dozens of six-toed cats.

Former headquarters of the KGB.

Step inside Lucy, the world's largest "elephant."

The remnants of two World's Fairs are here, complete with a 12-story globe, a mini-Manhattan, and a UFO-shaped pavilion.

The old observatory in Copenhagen has a spiral corridor used as a racetrack.

Ice cream stand, snack bar, and time capsule of milk conveyance.

Flamboyant architecture from the turn of 20th century.

Gargantuan home of Russian science.

Infamous marsh filled with toxic waste, World War II-era London rubble, and dead mobsters galore.

The tallest hotel in Europe.

The footprint of a frustrated devil in Munich's Cathedral.

Daily jousts and dancing barrel makers in Munich's mechanical clock.

A building so large that it has its own weather.

An organ located deep within a cave, whose "pipes" are the geological features of the cave itself.

Where the embers of the Big Bang were first detected.

Once a private collection, now the only museum of arms and armor in the Western Hemisphere - CLOSED.

Island ghost town detailing Flagler's folly in building the Overseas Railroad.

This 1000 year old relic-filled cave monastery and UNESCO World Heritage Site also hosts an amazing micro-miniature museum.