This skeletal, unfinished Gothic church once housed a miraculous masterpiece by Raphael.

A surprising and unconventional mosque hidden in the subsoil of Istanbul.

A marvel of Byzantine engineering under the streets of Istanbul.

Five sultans and their families rest in eternal splendor, teeming with overlooked beauty and drama.

1513 Turkish world map, full of European state secrets and snarky commentary.

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

This former Imperial summer home was the venue for a royal slap that once echoed 'round the world.

Rusted structures stand like ghosts of Cyprus' 6,000-year-old copper industry.

This 700-year-old Cyprus castle is the birthplace of the world's oldest wine, said to be toasted by Richard the Lionheart at his wedding.

The water here is so clear you can see the mysteriously sunken ship from the surface.

Breathtaking Byzantine paintings cover the inside of this 12th-century church.

This gem is often wrongly overshadowed by the larger, newer Metropolis church in Athens.

This small 16th-century church in Athens is almost entirely surrounded by a modern building.

Where commuters walk through remnants of an ancient Greek necropolis.

The oldest cemetery of modern-day Athens blends the modern and ancient worlds.

The site where hundreds of Greeks were tortured by the Nazi secret police is now a cosmetics store.

This ancient hydrological marvel is now the base of a modern outdoor cinema.

The railway carts travelers to central Athens's highest peak, which offers stunning vistas of the city.

Large collection from the 3rd millennium BCE.

A sharp sculpture made of thousands of pieces of jagged glass.

A sprawling collection of books and manuscripts about ancient Greece that would have put their famed libraries to shame.

"Unity, Creativity, Beauty."

A collection of art from Bulgaria's time as a communist state.

A vast Communist-era exhibition space in the Bulgarian capital.