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

The legendary cliffside castle of three-time Voivode of Wallachia, Vlad the Impaler.

A psychedelic tribute to one of Georgia's most unique artistic visionaries, out of place and time in the heart of Atlanta.

Hidden beneath the famous St. Peter's Basilica is a veritable city of the dead that may hold the remains of St. Peter himself.

This equestrian statue of Constantine the Great has been the subject of criticism for centuries.

Breathtaking and huge 430 year old maps of Italy.

One of Amsterdam's narrowest houses is located right across the canal from its widest.

A whimsical bridge adorned with decorative dragons.

A trough of 700 strange bronze faces runs through a narrow alley in Ljubljana's old town.

This 135-year-old weather station studied the effects of the climate on human health.

This sculpture used famed boxer Joe Louis as the inspiration behind its body.

An ancient Roman snake god, carved expertly into stone.

According to a gruesome legend, an architect sacrificed his wife to build this spectacular, 16th-century cathedral.

This fortress-like monastery is covered with intricate frescoes.

Visit an imposing 13th-century Transylvanian citadel lurking not far from the region's more heavily touristed attractions.

This metro station doubles as an unintentional paleontology museum.

After sitting unused for decades, this abandoned communist infrastructure became a wildlife utopia.

The kitsch mansion of the former Romanian president Nicolae Ceaușescu features a golden bathroom.

Religious structure known for its sculpted details.

An old spa town in the mountains of Romania where, according to legend, the great hero Hercules once bathed.

This memorial to the victims of the Romanian Revolution of 1989 is often compared to a potato on a skewer.

This Transylvanian church has changed its denomination four times.

A memorial museum to the political prisoners who were held at Sighet Prison, once one of the most feared places in Romania.

The ancient Greek Titan guards this massive dam holding a lightning bolt to symbolize electricity.