The 2,000-year-old Roman columns are hidden within Barcelona's Gothic Quarter.

Step inside the first house designed by Catalan architect Antoni Gaudí, considered to be one of the first Art Nouveau buildings.

Turntable anonymously received orphans, alms, and groceries.

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

Construction of Barcelona’s iconic (but controversial) church was finally completed in 2026—a century after the death of its architect.

This tea house was a hand-built gift from Boulder's sister city in Tajikstan.

A charming 17th-century alley is lined with secondhand bookstores and antiquarian shops.

Locals dubbed it the "Owl Building" because of its bird-like appearance.

Life's work of sculptor Elisabet Ney remains preserved in her last studio.

Free public park and gardens filled with peacocks and peahens.

Home to the largest urban bat colony in North America, estimated at 1.5 million bats.

This unique structure in suburban Austin is made up entirely of other people's castaways, and constantly changing.

A portly statue of a golden boy commemorates an unusual cause of the Great Fire of London: the sin of gluttony.

The watery entrance for condemned prisoners heading to the Tower of London is still visible along the Thames.

Six ravens are kept captive (but well-fed) at the Tower of London to prevent the fall of the Crown.

19th-century scientists would make the pilgrimage here to verify the precision of their measuring sticks.

A plaque hangs near the execution place of the Scottish Independence leader famously depicted in "Braveheart."

Public access to clean drinking water was an instant hit among the masses.

London's last remaining public soapbox site has seen speeches from Karl Marx, Vladmir Lenin, and George Orwell.

An easily overlooked stretch of ornate window fronts and gaslight lamps that could be right from the pages of Dickens.

The popularity of Sherlock Holmes led to the creation of his fictional address, turning the orderly London street numbers askew.

This South London cemetery holds the remains of more than 15,000 people.

A striking 500-year-old mansion provides an unexpectedly sublime home for live deer and a menagerie of exotic stuffed animals.

When it came to designing his own small office building, the eccentric architect wasn't afraid to show the world what he could do.