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

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

Meant to be one of the most extravagant hotels in the world, now an eerie, abandoned architectural gem in Mexico City.

One of the most remarkable caves in all of Iceland was created by a once raging river of lava.

This oceanside Reykjavik spot is speckled with recycled sculptures and large stones.

The final resting place of the controversial chess champion.

Iceland's first pagan temple in 1,000 years is underway in Reykjavík.

Cairns built to bring travelers good luck stretch across the land like miniature stone mountains.

Surrounded by ash fields in Iceland, an impossibly verdant valley looks like something out of a fairytale.

Two volcanic lakes in an enormous crater formed in a prehistoric eruption.

The Icelandic Sea Monster Museum explores the area's history of aquatic cryptid sightings.

Rising from the sea like a stone monster.

A well-preserved network of cavernous tunnels have spent silent centuries removing Toronto's waste.

This lavish estate recalls the opulent history of Calcutta.

Ornate, dome-topped cenotaphs fill this royal crematorium.

Made by a man on a worldwide sanitation crusade.

A startling, centuries-old subterranean marvel hides in plain sight.

World's most expensive home.

Where cemeteries are carved into the side of cliffs and infants are buried in the hollows of trees.

An eclectic mix of influences rot together in harmony in this India necropolis.

A nearly unconquerable island-fort in the Indian Ocean.

This abandoned fort is said to be the most haunted place in India, so much so that entry is prohibited after sunset.

A single tree's 2,800 aerial roots give the appearance of a complete forest.

This ancient Hindu temple is covered in thousands of colorful statues and has a long mythological history.