In the early Roman Empire, people deemed traitors and criminals were tossed to their deaths from this rock.

An ancient Roman temple first dedicated to an emperor's wife is now a church.

Historic fortifications form the boundary of Vatican City, but it’s not entirely surrounded by walls.

This striking, two-toned confluence of rivers is visible from space.

A beautiful opera house in the heart of Amazonia has recently restarted performances after a 90-year hiatus.

This futuristic bridge is one of the longest self-anchored pedestrian bridges in the world.

Legend says one of the world's largest marine geysers is actually a whale that got wedged within the rocks.

Once a meeting point for great thinkers, and the midpoint of the country.

The beautiful behemoth is one of the largest trees of its kind in the United States.

From Japan to Italy, this California park explores the world's cultures through their gardens.

Charnel house at the foot of Mount Sinai.

A basement full of treasures lies beneath this inn that has worn many hats throughout its 140+ years.

One of the most elaborate displays of Jellyfish is on display at the aquarium.

Steinbeck's old stomping grounds, immortalized in Cannery Row.

A dwindling menagerie of anthropomorphic oil derrick animals still dot the barren California landscape.

Explore the largest pure gypsum deposit in the world, and go dune sledding while you're at it.

The second-largest cave chamber in the world was discovered in 1898 by a 16-year-old and a friend known as "Pothead."

Just like the real 36th president of the United States, animatronic LBJ amuses visitors with jokes and stories.

A tribute to the "toughest woman on the Texas frontier," who survived a famous battle and five husbands.

Locals dubbed it the "Owl Building" because of its bird-like appearance.

This failed condo development was reborn as a street art hub.

Home to the largest urban bat colony in North America, estimated at 1.5 million bats.

An ivy-covered arch bridge dedicated to Tejano music singer and legend Rosita Fernandez.

All of Chicago's wood-paved streets are long gone but two alleys remain.