Construction of Barcelona's iconic (but controversial) church is expected to be completed in 2026—a century after the death of its architect.

Monasteries on rock pillars, once accessible only by frayed ropes.

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

The fifth-longest suspension bridge the world, connecting one Michigan peninsula to another.

Five candy-colored villages on the Italian Riviera.

In all of the 29 years it was in operation, no prisoners ever escaped successfully... or so they claim.

Behind this beachfront shop lies a spectacular, colorful sea cave with an equally colorful past.

The fairy tale castle of the "fairy-tale king."

Macabre astrological automaton clock dating to the late 1400s.

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

A hugely vast Irish landscape of barren rock that stretches for miles.

A lover's walk between hilltop towns, decorated with graffiti love notes.

This memorial commemorating fallen Swiss Guards of the French Revolution has been called the saddest stone in the world.

This historic covered bridge contains a series of macabre paintings that communicate one thing: everyone dies.

A chain of 16 wondrous lakes formed as a result of the gradual dissolution of soluble layers of bedrock.