This curious, round temple is the oldest still-standing marble building in Rome.

This ancient market is often referred to as the oldest shopping mall in the world.

A Nesting Doll of Churches.

Jesus' footprints and the first catacombs in the world.

Architectural monsters are devouring this palace's every door and window.

The only "Egyptian" pyramid in Europe and the legendary tomb of Remus.

2300-year-old Roman road connecting the empire.

A master of trompe-l'oeil creates a stunning, tourist-fooling dome out of a flat ceiling.

The yawning maw of this pagan visage is said to bite off the hands of liars.

This hidden Art Nouveau courtyard is an opulent feast for the eyes.

Hundreds of lucky felines haunt the ruins where Caesar was murdered.

The crypts of Capuchin friars decorated with the bones of over 4,000 friars, including an entire "crypt of pelvises."

Secret hideaway for an alternative beach experience.

The Midwest's reigning king of surplus stores is full of nothing you need and everything you want.

America's first National Historic Landmark is a 100-foot tall obelisk and gravesite dedicated to the only casualty of the Lewis & Clark Expedition.

The world's only three-story rotary jail is now a museum to a bizarre trend in prison design.

This zombie-themed restaurant stands out in the heart of corn country.

One of the most scenic stretches of road in America winds between some of the country's oldest trees.

A smoke stack so large, the Washington Monument could fit inside!

The lowest point in North America is home to an undrinkable pool surrounded by fields of geometric salt flats.

Aqueducts have dramatically changed this old lake, now home to tufa towers and its very own species of tiny brine shrimp.

Staircase winds down the side of Telegraph Hill through gardens, wild parrots flying overhead.

Quite simply the largest tree in the world (by volume).

The rocks in this arid basin leave trails of movement behind them.