Niagara Falls holds a special place in Nikola Tesla's history, so they put a statue on it.

Louise Bourgeois' 30-foot-tall steel spider sculpture.

This lovely, if imposing, piece of Canadian gothic is possibly the most photographed hotel in the world.

A horde of stray cats rule in this secluded Parisian cemetery under a bridge.

Over 50 exquisite hand-painted Renaissance maps decorate a Medici storage room.

This private skyway is filled with art and was expanded explicitly so that Hitler could appreciate a river.

This Industrial Age architectural and engineering gem helps visitors and residents alike traverse Lisbon, “The City of Seven Hills.”

The world's oldest bookshop still in operation.

Elaborate tile work in this railway station tells the story of Portugal.

A hidden three-foot-wide house separates these two regal churches.

Elaborately carved to showcase the glorious wealth that the age of exploration brought to the Portuguese empire.

A king's pet, a pope's gift, an artist's inspiration, and a tragic shipwreck.

Legacy of the earthquake that nearly wiped Lisbon off the face of the Earth.

One of the most beautiful bookstores in the world hides a neo-Gothic interior behind an art nouveau facade.

An ancient Egyptian temple in the middle of Madrid, Spain.

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.

Natural stone arches form a walkable "cathedral" at low tide, then disappear entirely when the water returns.

The oldest Roman lighthouse still in use.

Construction of Barcelona's iconic (but controversial) church is expected to be completed in 2026—a century after the death of its architect.

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

One of Antoni Gaudí's most classic buildings is well-known for its "dragon-back" design.

France's most famous cemetery, with some of its most curious tombs.