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

Turntable anonymously received orphans, alms, and groceries.

A stately palace has been converted into the world's largest cannabis museum.

Natural stone arches form a walkable "cathedral" at low tide, then disappear entirely when the water returns.

Spanning the El Chorro gorge, this pathway used to be one of the most dangerous crossings in the world.

Bacteria and algae give the salty water its bubblegum hue.

Wonderland replication in progress by one persistent man.

Bask in the 19th century grandeur of an eccentric Freemason millionaire's private gardens.

Barcelona's historic 19th-century sewers, whose foundations were laid in medieval times, are open to the public for exploring.

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

Hundreds of stone stairs and a winding medieval bridge connect this haunting Spanish island to the mainland.

The oldest restaurant in the world is this old-world Spanish eatery, still known for its suckling pig.

Madrid's romantically ornate crystal palace has been offering shelter to plants and art for over a century.

Gaze upon chocolate sculptures depicting everything from chariot races to Gaudí's famous church at this shrine to sweets.

This semi-secret storybook hedge maze is also the oldest garden in the city.

One of Antoni Gaudí's most classic buildings is well-known for its "dragon-back" design.

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