Elevated freight railway turned wildly successful urban park.

Amid the bustle and noise of the Financial District hides a secluded garden oasis above the city streets.

A crumbling hospital from the 1850s on Roosevelt Island.

Eighty million natural history specimens call this gargantuan museum home.

This colossal ancient sculpture of the monstrous Aztec rain god has a literally stormy history.

The Mexican painter Diego Rivera created this unusual museum to display his collection of pre-Hispanic artifacts.

This foreboding building was the headquarters of the terrifying Spanish Inquisition in Mexico.

This incredible college library is a visual masterpiece of mosaic art. It also looks kind of like a giant boombox.

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

The winter home of millions of migrating monarch butterflies.

The unique collection often goes unnoticed by visitors focused only on the archaeological objects.

You can release a young butterfly at this beautiful indoor garden.

An elaborate Mayan city shrouded in alien conspiracy revealed the tomb of Pacal the Great.

Clap your hands at the base of the pyramid, and the song of a sacred Mayan bird will echo through the air.

A museum in the former home of Marxist revolutionary Leon Trotsky.

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

The only castle in North America to ever house European sovereigns.

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

The famous artist couple lived and worked here, in two different houses connected by a bridge.

66,000 pieces of art, donated by one of the world's richest men.

Frida Kahlo's childhood home, now a museum of her life and works.

An 18th century wonder of the world, lost in WWII, re-created at the Catherine Palace.

Bali’s Mother Temple, a breathtaking complex that rises serenely up the side of an active volcano.

Of five volcanoes located in the massive Tengger caldera, this cone is the youngest and most active.