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

From Austrians to Nazis to Soviets, this historic Budapest fortress has a history as complex as the city itself.

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

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.

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

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

Sofia's legislative center is continuously reinventing itself.

A striking symbol of the Bulgarian capital.

This historic black and white monastery is one of Bulgaria's architectural jewels.

A mountain pass in Bulgaria's Balkan Mountains was the site of four historic battles.

A magnificent, glittering building tucked into a tiny Bulgarian mountain town.

An abandoned saucer-shaped monument in the Bulgarian mountains.

The ceiling of Prohodna Cave in northern Bulgaria affords a peek at the sky via two deity-sized-eye-shaped holes.

The bust of Romania’s most notorious ruler, Vlad Dracula aka "Vlad the Impaler," keeps watch over the ruins of his medieval court.

One of the most controversial statues in Romania is an emperor with no clothes.

Romania's triumphal arch looks out over Bucharest.

This solitary monastery may hold the remains of Vlad the Impaler (but probably not).

This elaborately decorated, fairytale-like Romanian royal palace is one of the most striking castles in Europe.

Conspiracy theories and occult legends surround this mysterious natural rock formation.

The European towns of Brașov and Râșnov each have proud signs reminiscent of the Hollywood sign.

The possible imprisonment of Vlad the Impaler here earned the medieval castle its nickname, "Dracula's Castle."

Gaudí's famously flamboyant architectural style is on full display in this sprawling park and garden.

A vista of the city and sea from atop the little-known viewing deck on an unassuming Columbus statue.