This uber-quaint Polish village is known for its habit of painting elaborate floral motifs on just about everything.

A fairytale Gothic castle steeped in Nazi treasure conspiracy theories.

This Nazi ruin was the site where Hitler was almost blown up by a suitcase bomb.

The site of the first battle of World War II.

The walls and ceiling of this Polish church are decorated with thousands of skulls, with another 21,000 skeletons just below.

Countless stories attempt to explain Poland's mysterious J-shaped trees.

Morocco's Argania trees are infested with nut-hungry goats.

A 19th-century mansion houses the largest collection of gin in the European Union.

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

One of Amsterdam's narrowest houses is located right across the canal from its widest.

The former home of a mad diplomat is said to still be marked in bloody, arcane scrawls.

A unique collection of gilded age mechanical pianos.

The largest collection of handbags in the world, the oldest of which were used to carry Bibles, primarily by men.

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

This impressive collection of rare books on ancient mysticism inspired author Dan Brown.

A beautifully eclectic mix of architectural styles.

Seven mini rowhouses fill the gap between 54 and 70 Westerstraat.

An ancient passage filled with stalls selling used books, once frequented by Vincent Van Gogh.

The attic of a four-century-old canal house hides a clandestine church.

This historic Amsterdam bar used to accept sailor's monkeys as payment.

Established in 1638 to battle the Black Death, Hortus Botanicus Amsterdam is a treasure trove of rare flora.

Cat art as far as the eye can see.

An Amsterdam street lined with antique shops each one dedicated to a different obscure collection.

The rusting hulk of a hand-powered, nearly 160-year-old submarine abandoned in 1869 due to the ravages of decompression sickness.