The hidden offices underneath Memorial Bridge have been locked up since 1976.

This Quebec estate is home to the elaborate gardens of a self-taught horticulturist.

This abandoned five-star hotel is now a five-star urban exploration destination.

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

The only Bahá'í house of worship in North America and one of only a handful worldwide.

A late-night restaurant empire was launched from this humble storefront.

A grove of "candelabra redwoods" deep in California's Lost Coast.

It took over 100 years to decode this enigmatic epitaph for two buried brides.

This charmingly homemade amusement park has been growing for 40 years.

Existing for more than four centuries, the last of Hakone’s historic teahouses serves a sweet, mold-based rice drink.

The first "Hut" was actually a small brick building.

During the holidays, a vintage subway train whisks New Yorkers back in time.

The hallucinogenic center of the ancient world.

This "Little Finland" started as a Finnish utopian society in Eastern Brazil.

An out-of-place Air Force radar dome is all that denotes this park as a former missile launch site.

Tropical paradise strewn with hundreds of World War II wrecks.

The ruins of an ancient island city built atop a coral reef in the South Pacific are spectacular and strange enough to have inspired H.P. Lovecraft.

A theme park that suffered massive flooding during Katrina was abandoned, and now proves irresistible to trespassing explorers.

This scalding hot river was thought to be a myth until one geoscientist made it his quest to study the mystical waters.

Hidden in Central Park's Ramble is a troublesome cave buried just beneath the surface.

The beautiful tunnel that ran from the lobby to Penn Station is still hidden underneath 34th Street.

One of the steepest streets in the United States makes an intriguing challenge for cyclists.

A once-booming Mississippi River town with a history of racial violence is now eerie and mostly abandoned.

An unusual but excellent display created in the 1930s as propaganda against the Freemasons.