A small island dotted with old, historic Finnish buildings.

This irregularly shaped sea fortress has defended not one but three different sovereign states.

Villas that once served as playgrounds for the rich now fall away in decay.

A lovingly curated curio shop in which the taxidermy wear newspaper party hats, and peanut shells are spread across every surface.

This endearingly discomfited urinating statue commemorates the sneaky pees had by us all.

An alien church provides much needed silence in the midst of a Finland shopping center.

A subterranean house of worship carved right out of the bedrock.

A Parisian cemetery where the elite and artistic are interred beneath an eccentric collection of tombs.

France's national museum of scientific and industrial instruments.

An iconic and eccentric bar for "Manouche" Jazz music keeps expanding its space—and its influence.

An off-the-beaten-path boutique stuffed with an eclectic collection of upcycled goods.

This little-known relic crypt holds stolen parts of a Roman Empress.

A popular shrine where the Blessed Virgin allegedly appeared in 1830, displaying a holy armchair and two incorruptible remains of Lady Saints.

A counter-culture bookstore like no other hides in plain sight in the streets of Paris.

A museum of carnival attractions where you are invited to ride the rides.

One of the oldest medical collections in Europe focusing on rare surgical instruments.

This iconic Parisian bookstore doubles as the "Tumbleweed Hotel" for traveling writers.

Notorious artist squat renovated into legal studios.

The macabre collection of Jacques Sirgent, an expert scholar on the undead and all of their trappings.

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

Gaudí's famously flamboyant architectural style is on full display in this sprawling park and garden.

These secluded and abandoned anti-aircraft defenses have become one the most scenic viewpoints in Barcelona.

This semi-secret storybook hedge maze is also the oldest garden in the city.

One of Antoni Gaudí's most classic buildings is well-known for its "dragon-back" design.