This unattributed sculpture in Amsterdam is hiding in plain sight.

A Dutch passageway's artistic, aquatic-themed makeover pays tribute to the capital city's famed waterways.

A beautifully eclectic mix of architectural styles.

A 16th century chapel decorated with bones, skulls, and entire bodies hanging from the wall.

This eccentrically decorated palace is replete with grottoes, fountains, tunnels, and caves.

A king's pet, a pope's gift, an artist's inspiration, and a tragic shipwreck.

Elaborately carved to showcase the glorious wealth that the age of exploration brought to the Portuguese empire.

The world's oldest bookshop still in operation.

This Industrial Age architectural and engineering gem helps visitors and residents alike traverse Lisbon, “The City of Seven Hills.”

One of the smallest bookstores on the planet.

The perfectly preserved underground rooms where Churchill plotted the war against Germany.

This ornate Victorian marketplace was the setting for Diagon Alley and the Leaky Cauldron in the Harry Potter films.

Thrilling and delicious complement to any dining experience.

Numberless clock creates a meal of time for the dreaded, insectile Chronophage.

All that remains of the fishing-vessel-turned-warship is its weathered hull.

The smallest pub in Britain was once a cabinet of curiosities and it still has the dead cat to prove it.

Unusual British home built to disguise a water tower.

A chaotic collection of coin-operated slot machines designed to delight and disturb in equal measure.

A magnificent Victorian garden that brings the charm and style of old-time aristocracy to the 21st century public.

This unusual 7th-century Frankish seal offers more questions than answers about its past.

New York's oldest magic store.

A treasure trove of artifacts, books, and artwork from the "golden age" of exploration.

A crumbling hospital from the 1850s on Roosevelt Island.

A tiny museum housed in a New York freight elevator specializes in the "overlooked, dismissed, or ignored."