Hollywood's most famous landmark, the "temporary" sign that has stood for decades longer than intended.

The last remaining relic of San Francisco's glittering 1915 Panama Pacific Exposition.

Elevated freight railway turned wildly successful urban park.

In all of the 29 years it was in operation, no prisoners ever escaped successfully... or so they claim.

An elaborate shrine dedicated to the four corners of the world unfortunately misses its mark.

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

The "World's Largest Underground Business Complex," a 55,000,000-square-foot city underneath Missouri.

Gargantuan home of Russian science.

Soaring over 6,000 feet in the Bavarian Alps, this beer garden was once Hitler's 50th birthday present.

This 19th century granite fortification is one of the most well preserved forts in New England.

Moscow's imposing monument to the Space Age.

A massive volcanic plug is now a protected area that hosts a number of bird species.

Few other hotels can rival the grandeur of the Castle in the Rockies.

World's second largest particle accelerator, where nature reveals its secrets.

The highest point in Alabama was almost completely deforested, but is now home to protected towers and trees.

This well-preserved Cistercian Abbey in a romantic pastoral setting has inspired artists like the poet Wordsworth.

A nostalgic bibliographic gem.

These 20-foot jaw bones honor a time when the leviathan bones were a sign that whalers survived the hunt.

The lighthouse central to the 1980s horror classic "The Fog" is, in fact, located in one of the foggiest areas of the Pacific Coast.

The highest point in Arizona is an oddly snow-topped peak within the otherwise arid state.

The ruins of this medieval castle in Northern Ireland have inspired artists from C.S. Lewis to Led Zeppelin.

A glacier pocked with ice caves and surrounded by rainforests.

Islanders once used this dramatic, otherworldly landscape to hide their cattle from Viking raiders.

The largest body of water in Massachusetts annihilated four small towns just to slake Boston's thirst.