Come face to face with the ferocious visage of the serpent-headed mother goddess of the Aztecs.

This influential Renaissance-era library was once the haunt of kings and monks.

This elaborate tunnel is the first structure composed of cast concrete in the United States.

Queen of the waterlilies, so big and strong it can support the weight of a human.

This bustling Italian plaza is built on the ruins of an ancient Roman amphitheater.

The largest 19th century panorama in the world still in-situ.

The second oldest Jewish graveyard in the U.S. is tiny, with connections to George Washington and Henry Wadsworth Longfellow.

San Francisco’s condensed garden of incredible plant growth.

This museum houses two of Mexico's most impressive Aztec monoliths.

Built for an exposition in 1915, these horticultural displays have stood the test of time.

One of Madrid's oldest trees, with a long and colorful history, resides in El Retiro Park.

One of the longest wooden benches in the world snakes around Geneva's Treille Promenade.

Affectionately known as "Lord Bot," this historic statue has a cult social media following and rightly claims to be “the most metal inhabitant of the Wren Yard.”

This small monument to the great inventor contains a time capsule and a Wi-Fi hotspot.

The façade of this building looks like a bingo board, but it's really a giant clock by a famed graphic designer.

A theatre built to house the rowdy Oxford graduation ceremonies became the stage for a debate about God's existence.

You can get anything you want at the former site of the restaurant immortalized by Arlo Guthrie.

Chicago’s incendiary role in the labor movement.

Where Agatha Christie mysteriously disappeared in 1926.

The ruins of an ancient stadium that hosted gripping chariot and horse races.

On the Hudson resides one of the largest clocks in the world.

The competition: breathe deeply as long as you can.

Ancient serpentine sacrifice holder that has stood the test of time.

America's largest man-made forest was planted in an effort to bring back the past.