Explore the dark underground corridors of this graffiti-covered former military fortification.

Its unique collection details the history of the state's svelte railroads.

Turns out you can see the world without ever leaving Maine.

A giant telephone commemorates the last "crank" call ever made in the U.S.

An unusually designed bridge from the 1920s was built to withstand the tides and winds of Maine.

One of the largest wooden ships ever built is honored by a steel sculpture evoking her once-superlative scale.

This tiny patch of arid sand sits in one of the greenest states in the United States.

This World's Fair showpiece was built in Chicago, but shipped to Maine.

The small town of Poulsbo in Washington state is the next best thing to the Kingdom of Norway.

A French chateau, failed utopian community, odd museum, and Stonehenge replica in rural Washington State.

The Canaima airstrip in Venezuela keeps an antique DC 3 plane in its camp.

The larger of two volcanic peaks rising out of the crystalline waters of the Caribbean.

This mountaintop lake bubbles and steams in a perpetual boil, thanks to its direct link to the Earth's interior.

This historic hiding place, often used by people escaping slavery, is a testament to a heroic struggle for freedom.

Built in 1512, the oldest cathedral in the Americas.

After Christopher Columbus died, his son built a fancy house to rule from.

The first official clock in North America, it kept time for the Spanish government of Santo Domingo.

The oldest colonial fortress in the Americas was once the home and later prison of Christopher Columbus.

The final resting place of Christopher Columbus - or possibly someone else.

This replica medieval European village in the Dominican Republic was built by a Hollywood set designer.

This beachside town is home to a diverse nature reserve, multiple cays, and one of the three bioluminescent bays in Puerto Rico.

Invading U.S. troops were first seen from this now-abandoned tower, leading to the Spanish-American War.

La Cara del Indio honors the Taíno chief who fought bravely against the Spanish invasion of Puerto Rico.

This former sugarcane transport tunnel is now a portal to a lovely beach.