Two very green residential towers cleaning the air in one of Europe's most polluted cities.

The iconic boulevard is the perfect place to catch sight of a bicycling skeleton, a levitating Satan, or a chef with his head stuck in a pizza.

A vista of the city and sea from atop the little-known viewing deck on an unassuming Columbus statue.

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

These secluded and abandoned anti-aircraft defenses have become one the most scenic viewpoints in Barcelona.

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.

This memorial to the victims of the Romanian Revolution of 1989 is often compared to a potato on a skewer.

A fire once nearly devoured this gorgeous 14th-century Gothic cathedral.

Romania's triumphal arch looks out over Bucharest.

The European towns of Brașov and Râșnov each have proud signs reminiscent of the Hollywood sign.

This snug medieval lane is one of the narrowest streets in the world.

The bust of Romania’s most notorious ruler, Vlad Dracula aka "Vlad the Impaler," keeps watch over the ruins of his medieval court.

The possible imprisonment of Vlad the Impaler here earned the medieval castle its nickname, "Dracula's Castle."

The pedestrian traffic signals in Brazil's teeming metropolis light up with clues to nearby landmarks.

Cars mysteriously roll uphill on this street.

A 125-meter long "tribute to the Brazilian people."

Beautiful public park off the beaten path and away from tourists.

The final resting place of the liberator of Argentina is guarded around the clock by two soldiers.

The humble tomb of an Argentine general, hand-built by his son using stones brought down from the Andes.

A vast necropolis where you'll find the elaborate mausoleums of Argentinian tango stars.

A beautiful young girl said to have been buried alive in her coffin…

A series of waterfalls so massive they straddle the border of Argentina and Brazil.

The design of the Palacio Salvo has been described as "a lighthouse on top of a building."