These biodiverse university gardens form a green oasis amid the urban chaos of Mexico City.

This fantastical house shaped like a seashell brings aquatic design to architecture.

These haunting ruins of a 700-year-old Prehispanic city have witnessed centuries of wars and massacres.

An Aztec temple, the largest man-made pyramid in the world, sits buried in earth with a Spanish church set on top.

No telescopes, no power, no gift shop: The Observatory of Chichen Itza, one of the world's oldest observatories, takes astronomy back to basics.

Visiting this cacophonous collection of vintage novelties is like stepping into the mind of a crazed toymaker.

A church dedicated to the Mexican skeleton saint.

Twelve natural mummies are displayed in the crypt of this former monastery school.

Every equinox this Maya pyramid puts on a spooky ancient light show.

An Aztec snake god has taken the material form of an apartment complex.

This North African stone complex is considered to be the oldest astronomical observatory on Earth.

This ancient monument has been dissembled and put back together at least twice.

A Portuguese Jewish cemetery filled with stunning grave monuments that date back to 1614.

Underground monastery and fortress.

Ancient rock-hewn town that witnessed key events of Georgian history.

An abused and forgotten metropolis, abandoned for centuries.

This architecturally eclectic fortress witnessed centuries of bloody turmoil, including the massacre of its ruling clan.

A small but hugely whimsical theater where marionettes play out the "The Battle of Stalingrad."

Fortified homes of highland warriors that are still in use today.

A gorgeous mural outside a beloved D.C. restaurant pays homage to famous Black Americans.

The oldest building in the District of Columbia was preserved because of a mistaken connection to George Washington.

The famous abolitionist’s preserved estate is one of Washington's finest monuments to its great Black citizens.

A quirky collection flush with information on commode culture from ancient times to modern day.

This beautiful natural train tunnel is said to grant the wishes of visiting lovebirds.