On La Gomera, "Silbadors" communicate in a 4,000-word language of whistles.

Originally used to sell brandy, the bull-shaped billboard became an iconic symbol of Spain.

Originally planted by the ancient Carthaginians, this sprawling palm grove is one of the largest in the world.

This enormous censer uses a pulley system installed over 400 years ago.

Long tunnels run under the ancient chariot racing circuit to the tower.

A towering monument in Spain has proven to be more labor-intensive than initially planned.

This beautifully verdant lagoon is tucked below a massive volcano in a crater atop a black pebble beach.

An eerie collection of the surviving structures from a past celebration of the future.

The chefs at El Diablo use heat generated by an active volcano to cook the food.

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

The largest Art Nouveau complex in the world is a Barcelona hospital with a 600-year-long history.

Stunning Roman aqueduct used for 1900 years and still standing.

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

Partially collapsed lava tube and cave system complete with concert hall, underground pond, and unique albino crabs.

Over two centuries old and counting, Madrid's massive botanical garden contains one of Europe's only desert environments.

An architect transformed this abandoned cement factory into his castle-like workshop.

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

This cemetery features modernist statues as strange as its name.

An ancient octagonal weather station named for the eight Greek gods of wind.

This ancient structure is widely thought to be the oldest intact pyramid in the world.

The massive cave church of Cairo's Zabbaleen community is one of the largest Christian churches in the Middle East.

Dozens of snakes are housed and worshipped within the walls of this Vodun temple.

An ancient burial ground believed to have been used for ritual sacrifice.

Ancient artists in the middle of nowhere.