This castle-fortress is a living example of the transition from medieval defenses to modern fortifications.

A modernist church in an ancient village.

"Alleys of Stone" form natural mazes in Spanish natural park.

This enigmatic Roman tower lurks just outside Belmonte.

A small sanctuary carved into the mountainside near the tallest point in continental Portugal.

A mosaic-tiled house built by graveyard sweeper Raymond Isidore.

The largest underground church in Europe.

A haunting medieval mural of the Danse Macabre graces the walls of this church.

These ruins reveal the remarkably intact layout of a Roman marketplace.

The 16th-century church was kept in its ruined state as a reminder of the casualties of World War I.

The remains of this ornate chapel now act as a portal to a cramped French cemetery.

A once drab public housing estate is transformed into a colorful gallery of trompe l’oeil murals.

For over 300 years this little carving has been the city’s good luck charm.

Strange red rock formations that have been attributed to a higher power for hundreds of years.

The ancient dwellings of the Puebloans, located in the cliffs of majestic mesas.

One of Mexico's least-visited archaeological sites is tucked away inside a theme park.

Costa Rican accommodation resembles a crash site, but with a nice balcony.

Military artifacts from the Salvadoran Civil War are displayed in this small but notable museum.

The world's largest military aircraft cemetery.

The biggest solar telescope in the world helps reveal the secrets of our sun.

A working cattle ranch with remarkably well-preserved prehistoric petroglyphs and ancient ruins.

A spiritual vortex among the red rocks in Sedona.

America's only nuclear missile silo open to the public.

A reproduction of earth's many biomes.