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

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

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

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

The stickered marker pinpoints where the only maintained road in the United States crosses into the polar region.

Permanent exhibit reminds visitors of the Exxon Valdez.

The ruins of a town wiped out by the second-largest earthquake in recorded history.

Running under an entire mountain, the longest highway tunnel in North America is kept fresh using portal fans and jet fans.

Internationally recognized group that works to protect the wolf and educate the public about its plight.

An Alaska livestock farm devotes itself to harvesting wool from creatures that once ran with mammoths and sabertooth tigers.

This small city where almost everyone lives in the same building can only be reached via North America's longest tunnel.

Four-story concrete hotel never opened to customers.

A trading post in the North Pole where children send letters.

The ghostly remains of what was once the world's richest copper mine.

The king of U.S. high points towers over every other peak on the continent.

Once a private collection, now the only museum of arms and armor in the Western Hemisphere - CLOSED.

Second largest wastewater treatment plant in the country.

Funded entirely by volunteers and donors this military memorial features a tank with a comedy line on its barrel.

Every December the Wannalancit Mills lights a Christmas Tree over the old mill's smokestack.

Built to bless whalers before their voyages, this Massachusetts church now features a ship-shaped pulpit.

This Cape Cod museum exhibits what it claims is the only authenticated pirate treasure in the world.

This supermarket is suspended 25 feet above an interstate highway.

In order to save this beloved rock, locals blew it up and put it back together piece by piece.

A historic custom house with ties to George Washington is now a shrine to local nautical history.