An ancient tomb that still stands in Portugal.

An 11th-century medieval castle cascades over the town of Numão.

This impressive rupestrian engraving dates back to the Upper Palaeolithic period.

This gaping hole in the middle of a remote mountain lake looks like a portal to another dimension.

Come for the bread-themed puppet show, stay for the buffet.

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

Ancient catacombs form the foundation for this Rococo orgy of a church.

This giant sculpture made of trash is a critique of society's wastefulness.

An early work of the architect Álvaro Siza Vieira, these swimming pools blend into the beach.

An abandoned tuberculosis hospital said to be haunted by the patients who died within its walls.

This abandoned naval battery stood at the ready as recently as the 1980s.

In Spain, the ruins of a Roman military camp sit along a flooded section of a river.

Rainwater transformed this old quarry into a peaceful pond you won't find in most tourist books.

One artist's collection of homemade handicrafts doubles as a monument to 20th-century material culture.

Portugal’s highest lighthouse has one of the most impressive focal planes in the world.

A micronation on an islet along the coast of a Portuguese island.

Men in rubber-soled boots serve as your "brakes" on this toboggan ride Hemingway described as "exhilarating."

Rolling sand dunes of the Sahara... in the middle of the Atlantic Ocean.

This ship carrying cargo and four church bells for the Catedral Metropolitana Nossa Senhora Aparecida ran aground in 1968.

Once a bustling fishing village and trading post, today these Cape Verde ruins provide a home only for seabirds and turtles.

Did Gustav Eiffel design this enigmatic metal building?

A perfectly circular lake is formed by the crater of an ancient underwater volcano.

One of the few remaining casualties of the London Blitz, this destroyed church has become an enchanting public garden.

London's creepiest cemetery was once the site of dueling magicians and mobs of stake-carrying vampire hunters.