A Byzantine church containing the holy remnants of three saints sits atop the site of an ancient temple.

This building displays the scars of the “Dekemvriana,” a dark time in modern Greek history.

Where commuters walk through remnants of an ancient Greek necropolis.

The famous sculptor left his mark on this Italian wall in an internationally protected example of street art.

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

The ruins of a fifth-century church dedicated to Our Lady of the Harbor.

Legend holds that St. Paul was flogged for preaching Christianity at this pillar.

The ancient mosaics here are considered among the finest in the world, and serve as a stunning record of Greco-Roman daily life.

Beneath an ancient wishing tree lies an underground chapel with 12th-century frescoes and catacombs dedicated to a lady saint.

An ancient necropolis of magnificent tombs.

A Byzantine-era church hidden in a wooded area below the Acropolis.

The site where the summer solstice helped ancient Greeks sync the lunar and solar calendars.

Cliffs full of fossils at the portal to England's Jurassic Coast.

The engineering wonder and pleasure dome of a much-maligned emperor still holds undiscovered secrets.

The ruins of the largest gladiatorial school in Rome are largely hidden under modern streets.

A rather vulgar example of the transition from Latin to the Italian vernacular.

A Nesting Doll of Churches.

This Roman amphitheatre was also the location of the first gladiator school.

Unscathed for almost 2,000 years, the best preserved Roman triumphal arch is in a small southern Italian city.

According to the legend, this structure was built in a single night with the help of the devil.

Also known as the Temple of Poseidon, this is one of the best-preserved Greek temples in the world.

The only visible remains of this ancient Greek underground temple is its roof protruding from the earth.

For decades, vendors have sold clothes once worn by American soldiers who stormed Italy in the 1940s.

Well-preserved, still-functional sliding wood doors from Ancient Rome can be found in this Vesuvius-stricken house.