A 16th-century monastery boasts a lush array of plants native to Mexico’s most biodiverse region.

Many people don't realize there’s a lot going on in—and below—the world’s tallest triumphal arch.

This ornate church designed by a self-taught architect is an eclectic masterpiece in the heart of Central Mexico.

Just outside Lesotho's capital city, a rock formation takes the shape of a powerful predator.

There is only one place in the world where the corners of four nations come together.

"Respectful to the dead, safe and sanitary to the living, dedicated to the Genius of Memory..."

An ancient Scottish rock formation said to be the gravesite of a giant remains ensconced in legend and intrigue.

Built on a medieval synagogue, this church has a burial crypt, tunnel system, and Jewish ritual bath hiding deep underneath.

Italian cave with exceptional acoustics and an unsavory history.

A hidden tunnel of bones in one of Malta's oldest churches.

The floor of this spectacular Baroque sanctuary is covered in memento mori.

Burial grounds for more than 1,000 bodies deep under the modern town of Rabat.

Stone Age solar temple is aligned with the sun on each equinox and solstice.

Gaudí's famously flamboyant architectural style is on full display in this sprawling park and garden.

Construction of Barcelona's iconic (but controversial) church is expected to be completed in 2026—a century after the death of its architect.

A sculpture of a giant hand reaches for the stars in the middle of the Atacama desert.

The Andean town where every single building is decorated with a brightly colored frieze.

This small cave in the center of Isla Colon doubles as a sanctuary.

These mysterious ancient stone spheres were created by a civilization lost to time and are now mostly lawn ornaments.

This group of small islands on Lake Nicaragua formed after an eruption of the Mombacho volcano.

The youngest volcano in Central America.

Hidden deep in the Guatemalan jungle is a turquoise paradise of natural pools, caves, and waterfalls.

This $62 million dollar temple was erected to house one little dental fragment of religious history.

Singapore's landscaping project is home to 18 incredible Supertrees.