A poem by Arthur Rimbaud is inscribed on the wall of a street that, while it is only one block long, plays a key role in multiple novels.

An overlooked marble is the only surviving in-place 18th century example of the measurement that changed how we define distance.

This former “ante-chamber to the guillotine” has been refurbished to illustrate the brutal history of French justice.

This 18th-century sundial was designed to calculate the date of Easter each year.

Site of a classic 19th-century physics experiment to prove the earth is rotating.

Once a 19th-century brasserie, this McDonald's exterior celebrates Alsatian design and the "King of Beer."

This innocuous-seeming building is actually the remnant of a major wartime brothel.

The Sun King's military models, saved from the Louvre.

Twelve grave-faced marble angels guard the emperor's tomb at Les Invalides.

Hidden beneath the streets of London is a secret subway that only carried mail.

This well-preserved Cistercian Abbey in a romantic pastoral setting has inspired artists like the poet Wordsworth.

You can enjoy a (possibly haunted) stay at the medieval Norman castle that was once a favorite hunting lodge of King John.

A nearly 500-year-old sculpture depicts a man eating a sack of babies, and no one is sure why.

An unassuming rod in the Netherlands was once the old standard unit of length for the entire Dutch empire.

'The Letters of Utrecht' lays out a ribbon of poetry one letter at a time, with no final verse in sight.

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

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

A floating cat sanctuary on an Amsterdam canal.

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

This 17th-century house has a long and colorful history.

This public library and its impressive collection of academic books have not changed since the 17th century.

The oldest skyscraper of Europe now stands dwarfed by the surrounding structures.

These slanted cubic abodes are a creative if odd solution to a zoning pickle.

Old ships and machinery fill a historic harbor in the city that's home to Europe's largest port.