A student driver's nightmare.

An alleyway plaque is all that remains of the independent Texas' envoy that forgot to pay their rent for over a century.

Wedged between two buildings at the Great Ormond Street Hospital is this secret music installation.

The signs of a long buried road can still be found hidden beneath a London sewer grate.

The only university zoological museum in London houses extinct animals, bizarre natural history specimens, and a Micrarium of microscopic creatures.

This shop and gallery is a modern-day cabinet of curiosities, unassumingly positioned along an urban thoroughfare.

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

This churchyard arbor is surrounded by hundreds of gravestones placed there by author Thomas Hardy.

The widest waterfall in Europe is a natural wonder and one of the only places where fish are caught in the air.

A historic scientific breakthrough that crosses nine borders.

The sad remains of a monument to martial arts legend and movie star Bruce Lee—in the middle of Balkans.

This surreal memorial/cemetery is a necropolis of crumbling stonework and puzzle-shaped headstones.

Bridge that died in war and was resurected.

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

The "dragon babies" of southeastern Europe.

Castle and secret tunnel withstood a siege until its owner was killed by the Holy Roman Empire, while sitting on the toilet.

This massive subterranean fissure is known as the "underground Grand Canyon."

An ancient knight and a symbol of the city's freedom.

An eclectic art form practiced by untrained masters is celebrated at this museum in the heart of Zagreb's old Upper Town.

A wunderkammer of gold and silver reliquaries and ancient saintly bones.

This scale model of our solar system hid in plain sight for years before a physics team sought out all the planets.

Longest fortress system anywhere in Europe.

Gargoyle head that brings good luck.

A wonderfully strange collection of 500+ stuffed frogs doing people things.