High atop the Eiffel Tower is a small apartment built exclusively to entertain the science elite and make the rest of Paris jealous.

This structure atop a craggy cliff in one of the most beautiful parks in Paris boasts an unbeatable view.

Spanish architects used seized Muslim gravestones to rebuild parts of the fortress.

With a facade that measures just 107 centimeters, this five-story building is one of the skinniest in Europe.

A daily pyrotechnic celebration marks a beloved tradition during Valencia's festival season.

This amazing example of Valencian Art Nouveau looks more like a cathedral than a public market.

This massive fiberglass Gulliver turns every visitor into a Lilliputian.

This ancient amphitheater was restored in the early 1990s.

The last of three massive blast furnaces that were once at the foundation of the Port of Sagunto economy.

This beautiful spit of land was once the summer playground of the king of Spain.

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

This futuristic observatory at the top of the Pyrénées offers unrivaled views.

Ancient paintings known as the "Sistine Chapel of Cave Art."

This submersible road connecting a French island to the mainland is lined with safety towers for when the tide strands travelers.

Massive puppet-automaton machines created by French artist collective Machines de l’Ile.

This crack in France's seaside cliffs once hid a sinister secret.

Wall after wall of this French seaside neighborhood is intricately decorated with seashells and corals.

Bordered by forest on three sides and the ocean on the other, the Great Dune of Pilat is the highest sand dune in Europe.

The world's largest reflecting pool is just two centimeters deep.

A young Gustave Eiffel assisted in the construction of this skinny metal observation tower.