Five million people are laid to rest here, more than the population of Madrid itself.

The walls of these four caverns are filled with art that dates back to the earliest human presence in Europe.

The Roman city was the birthplace of various emperors and is home to one of the empire's most impressive architectural feats.

Remains of the lost church hide beneath this Spanish Parliament building.

This imposing modern citadel started out as a home renovation project.

The ruins of an ancient stadium that hosted gripping chariot and horse races.

This local emblem is the oldest and largest dragon tree in the Canary Islands.

This abandoned, turn-of-the-century astronomy hub is now the subject of more photographs than it ever took.

The ruins of a 2,000-year-old Roman fishing village perched on one of the best beaches in Spain.

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

Spain's stunning solar energy plant.

Remarkably intact Roman stone fortifications have encircled this Spanish city for centuries.

The largest prehistoric cemetery on the Balearic Islands dates back over 2,500 years.

According to the Guanches, the aboriginal people of the Canary Islands, the king of evil lives inside this volcano.

Two towns are linked by an engineering marvel masquerading as a boring suspension bridge.

A breathtaking and biodiverse wilderness in the mountain setting of Ernest Hemingway's "For Whom the Bell Tolls."

12th-century holy complex shares land with a natural park full of heavenly waterfalls and raptors.

You can soak in three relaxing pools filled daily by the tide.

A micro-communist utopia in Spain with no police, no mortgages and full employment.

Stuck in the middle of a modern Madrid city block are the remains of a 19th century sports complex.

A contemporary art installation housed within a Gothic cathedral.

A Spanish artist builds his own castle.

Seaside ruins of a settlement that date back to the first century B.C.

This remarkable prehistoric town is full of watchtowers and houses that have withstood thousands of years.