This geometric feat is a testament to the Incas' mesmerizing architectural abilities.

An Inca spa, military outpost or maybe… both?

The stones of this Incan wall complex fit together so well you couldn't fit a piece of paper between some of them.

Tucked away near more famous landmarks lies a statue meant to symbolize the confluence and continuing development of human culture.

Museum dedicated to the terror regimes of Hungary.

A trail of iron footwear stands as a monument to the thousands executed along this riverbank during WWII.

This ancient Greek place of assembly and marketplace is being revealed layer by layer below the modern Athens cityscape.

The tradition of open-air secondhand and antiquarian bookselling in Paris dates back to the Renaissance.

An "inside out" building in the historical center of Paris, featuring Europe’s largest modern art museum.

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

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

The ruins of an abandoned medieval city where the last Byzantine emperor was crowned.

Modernist design and funerary customs meet Spartan traditions in this one-of-a-kind graveyard.

The perfectly preserved underground rooms where Churchill plotted the war against Germany.

This 1967 experiment in modular architecture was designed to be a new model for urban living.

Despite attempts by local police to discourage it, Beatles-inspired graffiti has been a means for artists to air grievances for decades.

This tipsy office building in downtown Prague was originally called “Fred and Ginger.”

Macabre astrological automaton clock dating to the late 1400s.

One of Antoni Gaudí’s earliest buildings, built between 1886 and 1890 for the industrialist Eusebi Güell.

An unusual stroll through gentlemen's erotica demonstrates that pornography is timeless.

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

A 16th-century Andalusian palace.

The world's largest wooden structure.

Jesus' footprints and the first catacombs in the world.