The glowing blue Nymphaeum of Emperor Tiberius.

An Italian crevasse filled with abandoned buildings gives visitors a look at the world without humans.

A submerged archeological park still holds the wonders of a Roman Sodom.

The oldest volcanology research center in the world.

Pompeii's less famous neighbor is still revealing her secrets.

Every day is like Christmas on this street where the traditional Neapolitan nativity scene comes to life.

An abandoned railroad tunnel is now filled with bioluminescent bugs.

Known as the leaning temple, the sacred structure has somehow developed a severe nine-degree slant.

This 6th-century church has the largest and best-preserved collection of Byzantine mosaics outside Constantinople.

This commanding mausoleum holds the remains of Muhammad Ali Jinnah, the founder of Pakistan.

Perched atop the highest hill in Cartagena, this 17th-century convent offers spectacular views of the city.

This ancient fortress in Iran was once the oldest and largest treasury in the world.

The ruins of an abandoned medieval city where the last Byzantine emperor was crowned.

This magical space partly designed by Antoni Gaudi is one of the best examples of romantic gardening in the Mediterranean.

A science fiction-inspired apartment building designed by a famous Spanish architect.

A little-visited waterfall in an otherworldly landscape.

A Milanese café entirely designed by the American director Wes Anderson.

One of the most well-preserved temples of ancient Egypt.

The tower in this 1,000-year-old mud-brick village seems to vibrate for no apparent reason.

An arresting temple full of mosaics as colorful as the politician they memorialize.

A striking sculpture built to honor the women of the Lakota and Dakota Nations.

For six months of the year, three giant mirrors direct a pool of sunshine onto this otherwise occluded town.

The abandoned ruins of a beautiful medieval castle just outside Barcelona.

Yup, that's a 330-foot yacht passing over the highway.