This fortress dates back to the 6th century and is also the site of a controversial abandoned restoration project.

This massive monument was unveiled the day Kosovo declared independence from Serbia.

A fountain standing as a testament to a doomed alliance.

An Art Nouveau gem hides beneath the layers of city grime obscuring this once-magnificent building.

This remarkably well-preserved Egyptian plinth is pretty well traveled for a giant piece of stone.

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

A marvel of Byzantine engineering under the streets of Istanbul.

Climb a steep hill in 90 seconds on the second-oldest urban subway in the world.

Sofia's legislative center is continuously reinventing itself.

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

"Holy Wisdom" overlooks the city that became its namesake.

A striking symbol of the Bulgarian capital.

17th century palace once a meeting place for politicians.

Romania's triumphal arch looks out over Bucharest.

This communist behemoth is the heaviest building in the world and a legacy of a brutal regime.

This once-derelict building is now one of the most beautiful bookstores in the world.

A collection of items from a way of life that no longer exists.

A diminutive statue that was inspired by the sculptor's own daughter.

This quaint Hungarian railway system is operated exclusively by children between the ages of 10 and 14.

A Trabant car, a kangaroo statue, and a plethora of plants take over this abandoned-factory-turned-bar.

The geographical center of Budapest is marked with a 10-foot-tall stylized zero.

Built in 1870 at the bridge that connected Buda and Pest, this spectacular incline railway was almost lost forever during World War II.

Some of the greatest minds in the history of Hungarian art and science converged in this café.

Built to give thanks for the passing of a plague epidemic, this cathedral is a one-of-a-kind architectural hybrid.