Three floors of musical instruments coming from all corners of the world and hundreds of years of musical history.

Lavish royal estate punctuated with heated greenhouses.

A wonderfully kitsch bookstore the size of a supermarket.

Only museum in the world devoted to bookbinding and book arts holds a permanent collection representing five centuries.

This Greek temple, open only an hour a day, was the site of a war of tastes between an architect and an artist.

A floating cat sanctuary on an Amsterdam canal.

Museum in a swimming pool where the water still flows.

This triumphal arch celebrating the Sun King's conquest of Lille is a masterpiece of military architecture.

Tables of secondhand books fill the inner courtyard of this 17th-century stock exchange.

The bronzed skull of a beheaded traitor was affixed to the city gate in the 17th century.

Christ's blood preserved in a Belgian town.

Potato-peeling mannequins, Inca art, and a dangling tuber mobile help trace the history of fries at this Belgian museum.

This wooden hotel is a temple to German sustainability and forest conservation.

Hamburgers are intensely proud of their tunnel beneath the river.

Once the tallest building in the world, this abandoned church is now a monument to the destruction of WWII.

The last inhabitants of one of the U.K.'s most remote islands were evacuated in 1930.

An 80-year-old plane tree is devouring an iron bench at Ireland's oldest law school.

A church filled with the bones of hundreds of virgins martyrs—or so they say.

Go inside a revolutionary, cage-less zoo where 70 species of monkeys roam free alongside their human visitors.

This beautifully designed star-shaped fort was the premier defense system of the late 1500s.

Three connected pink triangles memorialize persecuted gays and lesbians throughout history.

A beautiful maze marks where three countries meet.

A Portuguese Jewish cemetery filled with stunning grave monuments that date back to 1614.

Inspired by "The Starry Night" this Dutch bike path turns into a glowing work of art each night.