The ornate miniature mansions were built for Istanbul's feathered residents.

Hidden just under the waters around this Turkish island are the ruins of a once great city.

This famous city eluded concrete detection until the early 2000's.

This hunter-gatherer architecture is believed to be the oldest religious complex known.

A deadly ancient portal to the underworld.

These tombs were built into the side of a mountain so that ancient angels could reach the dead.

A marvel of Byzantine engineering under the streets of Istanbul.

Roman ruins top white travertine terraces formed by ancient hot springs.

In this historic region, homes and churches are carved into ancient volcanic rock formations.

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

The remains of the left arm of the levitating philosopher-saint are kept in a 13th-century Neapolitan basilica.

The burial place of an obscure North African saint was turned into a macabre body preservation factory for the 17th-century Neapolitan elite.

This magical-looking island is notorious for the misfortunes suffered by its owners.

This shining multicolored metro station deep under Naples is said to be the most beautiful in Europe.

Plaques on its facade commemorate the Tiber's most destructive deluges.

A deep mark on the remains of a Roman temple, believed to be left by a legendary warrior.

A statue representing a lost Roman profession that was vandalized for centuries.

Romans decided this 16th-century "talking statue" was so ugly, they named it after a primate.

A sculpture serving as an homage to Pope John Paul II.

The best preserved Paleochristian basilica in Rome hides a number of oddities and secrets.

A treasure trove of Renaissance-era funerary art in a Roman church built on top of Nero's grave.

Brass cobblestones mark the places where individual Holocaust victims were taken from their homes.

The spot where the fascist dictator made some of his most famous speeches including declaring war on Britain and France.

This mosaic-lined medieval church was built by the world's first admiral and still holds mass in ancient Greek.