One of the best examples of the modernist movement in Madrid.

Built on the foundations of an ancient Roman villa, the unique architecture of this castle on the Catalan coast was used as a set for 'Game of Thrones.'

A prehistoric cave in Spain contains paintings dating back to the Ice Age.

The odd cement nubs littering this Spanish square are actually the entrances to a series of buried silos.

Meant to resemble a massive tree, the building is the best example of Spanish organicist architecture in Madrid.

This 17th-century manor house provides a fascinating glimpse into old-world Mallorcan life.

This exhibition space designed to look like the skeleton of a whale is hidden underground.

This medieval fortification has weathered the centuries better than any other structure from its era.

Replica of Seville, Spains famous Giralda, a former minaret converted into a bell tower.

This fountain was designed to honor the man who helped bring water to Barcelona.

The legendary bathing site of a Moorish queen is actually part of a Roman fish farm.

This abandoned racetrack looks like it is set to hold competitions in the apocalypse.

This small, lush island has a long and bloody history.

This house covered in small stones was the work of one man over the course of nearly 30 years.

From grand battles to daily life, this Spanish museum offers a view of world history in miniature.

The two massive guns that defended Cartagena Bay.

These "mermaids" that surround a plaza in Segovia are rather sphinx-like.

Sample Spanish wines under frescoes in a historic monastery of "barefoot old men."

Continental Europe's only museum devoted to salt and pepper shakers features more than 20,000 designs.

A series of well-preserved ruins show the culture of the ancient Benehoaritas people.

This 18th-century project to build the world's tallest gravity dam was never completed.

The oldest operating roller coaster of its kind, the Montaña Suiza has been thrilling riders since 1928.

A pre-Hispanic pyramid in the middle of a tourist district in the Canary Islands.

This historic electric train has operated with regularity since the early 1900s.