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

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

This ancient theater, restored in the 20th century, lives on as a venue for dramatic and musical performances.

A gigantic statue of a Russian soldier watches over the ancient city of Plovdiv, a prominent reminder of the Soviet period in Bulgaria.

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

Ruins of a German Castle on top of a towering stone pillar.

A preserved college lock-up that recalls a clubhouse approach to discipline.

It's good luck to be mocked by this monkey.

Albert Einstein's head sticks out of a snail shell stacked on a rocket in this truly bizarre monument to the scientist.

The world's tallest church tower reveals a spectacular view to anyone up to the task of climbing the daunting staircase.

This strange statue features a bust of the famous composer plopped atop a woman's body.

Terrifically morbid cemetary and site of famous Paracelsus' grave.

These 12th-century catacombs carved into a mountainside were a place of mysticism and Christian hermitages.

The beautiful, ornate weather station is the most popular geocache in Salzburg.

Amidst medieval and baroque buildings, five human-sized gherkins stand tall.

Ugly 18th-century dwarf statues living in a perfectly landscaped Austrian garden.

This spire on an Austrian mountain is wrapped around a long spiral slide and has the world's tallest wooden observation deck.

Go inside to really appreciate this 500-year-old technological masterpiece.

Thousand-year-old Viking runes adorn an ancient Greek lion at the entrance to the Venetian Arsenal.

This Venice bookstore has resigned itself to constant flooding by keeping its books in bathtubs and boats.

Where Venice's gondolas go for a tune-up.

In the past, Renaissance sex workers were encouraged to entice customers on this bridge.

Las Vegas's very own 40-foot-tall fire-spewing praying mantis.

One of the world's tallest Ferris wheels takes visitors high above Las Vegas in a spinning party room.