This elaborately decorated, fairytale-like Romanian royal palace is one of the most striking castles in Europe.

Conspiracy theories and occult legends surround this mysterious natural rock formation.

The Tudor-style cottage in the middle of the square is not quite what it seems.

The last four extravagant street signs of London's historic banking street.

Six ravens are kept captive (but well-fed) at the Tower of London to prevent the fall of the Crown.

The watery entrance for condemned prisoners heading to the Tower of London is still visible along the Thames.

A historic freight system that found the true gold rush is in tourism.

The facade of this relic from the Klondike gold rush is decorated with over 8,800 pieces of driftwood.

This eccentric folly house was designed by Romanian thinker Bogdan-Petriceicu Hasdeu, with a helping hand from his deceased daughter's spirit.

Noirish green neon marks the location of one of the oldest private detective agencies in France.

A lone cannonball remains lodged in the walls of the Hotel de Sens as a sober reminder of a revolution.

Walk upon the mementos of the dead in this Parisian courtyard paved with medieval tombstones.

A mechanized clock where a man fights off a dragon, crab, and rooster.

César Baldaccini's iconic sculpture of a 40-foot thumb stands tall in La Défense.

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

The celebrated eyesore created by starry-eyed sweethearts.

A 16th-century fountain marks the site of a lost medieval cemetery once filled with mass graves.

Twelve grave-faced marble angels guard the emperor's tomb at Les Invalides.

This life-size replica of the Statue of Liberty's flame is also a tribute to Princess Diana by default.

This former “ante-chamber to the guillotine” has been refurbished to illustrate the brutal history of French justice.

The curious underground history of keeping Paris clean.

An "inside out" building in the historical center of Paris, featuring Europe’s largest modern art museum.

Medieval museum built over Roman baths that features famous tapestries of a lady and a unicorn.

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