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

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

A hidden church in a hidden courtyard tells the story of the Miracle of Amsterdam.

In the days before house numbers, these colorful signs held clues about various buildings' purposes.

A line number in Amsterdam that will likely never be used again due to its tragic history.

A floating cat sanctuary on an Amsterdam canal.

Amsterdam's narrowest house facade is a monument to 17th-century tax evasion.

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

Europe's official "zero-level," the equator of elevation.

A public urinal so pretty, it was declared a national monument.

This gorgeous reading room houses the oldest and largest art history library in the Netherlands.

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

Brussels' favorite peeing boy has a sister.

The Devil’s own choice when he needs a drink in Brussels.

A little sculpture with a large wardrobe.

A bronze statue of the fictional character nicknamed "Mrs. Hat" from a beloved Belgian comedy.

The compass on its front was a handy tool for 17th-century merchants who needed to know the direction of the wind.

A shining memorial to a Belgian hero is said to bring luck to anyone who touches it.

The somber sculptures commemorating Irish Famine on the river Liffey in Dublin.

The gorgeous library at Trinity College is home to remarkable treasures of Irish identity.

This courtly monument celebrates an influential comedian who turned taking the piss out of the powers-that-be into an art.

The 19th-century pharmacy (now a used bookstore) was featured in James Joyce’s "Ulysses," and has changed very little to this day.

The house where the writer spent his formative years.

The comedy and tragedy of Oscar Wilde is preserved in a Dublin park, captured in a sculpture of colorful stone.