Underwater art project will double as a massive artificial coral reef to help regenerate the damaged ecosystem.

A small collection of iguana-infested ruins hides amid Cancún's bustling hotel zone.

This masterpiece of muralism depicts the rich culture of the people of Michoacán and their timeless connection to the land.

This feature of the city's aqueduct has achieved numismatic fame thanks to its appearance on Mexican banknotes.

This amazing example of Valencian Art Nouveau looks more like a cathedral than a public market.

These unusual rooms on wheels are holdovers from the 1960s.

The Aldie Gristmill was once the largest factory of its kind in Loudoun County.

This pun was simply waiting to come to life, and one defense contractor made it so.

The largest cemetery for enslaved people in Loudoun County was almost lost to history, if not for the research of a minister.

Designated as an Underground Railroad research site.

Named for a Greek oracle that interpreted the words of Zeus, this beautifully-restored manor home was once home to the architect of the Marshall Plan.

This abandoned horse racing track was an exercise in hubris from its inception.

This sinkhole in the Arizona desert is filled with carbonated, arsenic-rich water

Originally conceived as part of a proposed Arizona State Capitol building in the 1950s, this structure built in 2004 stands as a monument to the architect's legacy.

The massive, incredibly rare instrument is over 11 feet tall with a range so deep it goes lower than humans can hear.

A geological mystery on Camelback Mountain.

This immigrant bridge once spanned the Thames but is now a fixture of an Arizona city.

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

What is the Thing?

Ancient pueblos built into the base of a natural canyon wall.

A spiritual vortex among the red rocks in Sedona.

This historic national park is covered in the stunning ruins of red rock pueblos.

Eons ago, a rushing lava river formed this pristine passage through solid rock.

A self-built castle made by a mysterious man.