The remains of a doomed Antarctic plane, buried beneath layers of ice and snow, await those willing to do a bit of digging.

Nimrod Polar Expedition base, and home to hundred-year-old frozen whisky.

Scientists use one of the saltiest bodies of water on Earth as a terrestrial base for studying water on Mars.

Largest sub-glacial lake ever discovered.

Natural time capsule containing an alien ecosystem.

The Pentagon sits on a former island that was in Virginia at low tide and D.C. at high tide.

These expertly crafted, scientifically accurate glass sea creatures were once an international phenomenon.

A place for ship-lovers to watch the passage of freighters traversing the Great Lakes while learning about their history.

The stone marker that Mason and Dixon placed at the eastern end of the famous north-south border they surveyed.

In this German city center, the streets have no names.

The "Key of Keys" for Washington, D.C. and the apocryphal landing place for the military campaign that started George Washington's career is now at the bottom of a well.

One in a series of historical markers from the massive 19th-century undertaking to map all of India.

An iron monument on the 120th meridian as surveyed, one of only four marking the boundary between Nevada and California north of Lake Tahoe.

A volcanic core jutting above the plain between the Snake and Boise Rivers, a marker identifies the reference point for all U.S. Government Surveys in Idaho.

One of the longest wooden benches in the world snakes around Geneva's Treille Promenade.

This stone in Lake Geneva was once the reference point used to determine altitude in Switzerland.

What many consider the original prime meridian and westernmost point of the old world.

This mundane post marks the old location of the city's main postal hub.

A concrete arrow from a 1920s network of airmail beacons is still preserved at the western edge of suburban Reno.

The centuries-old trees are draped with Spanish moss to make them look like wizened elders.

Locals call this magical moss-covered walkway the "Emerald Path."

An unexpected must-see for fans of Star Wars who find themselves on the beautiful island of Sint Maarten.

Where Saint-Martin ends and Sint Maarten begins (or vice versa).

A well-preserved example from a 1920s network of airmail navigation arrows sits near Interstate 15 in southern Nevada.