Famously misunderstood wonder of the ancient world

An Australian lake whose pink hue defies scientific explanation.

The sound of swaying stalks in this stunning grove has been named a governmentally recognized sound.

For two weeks every June, fireflies in the Smoky Mountains perform an astonishing light show.

This jaw-dropping 19th-century bridge uses its reflection to form what appears to be a perfect circle.

A massive underwater sinkhole made famous by Jacques Cousteau.

Medicinal spa created with the discharge from a geothermal energy plant.

An Italian crevasse filled with abandoned buildings gives visitors a look at the world without humans.

An exquisite tunnel of cascading flowers.

On Japan's Tashirojima Island, cats are king.

This astonishingly geometric cave has inspired everyone from Jules Verne to Pink Floyd.

This rare triple-jurisdiction drawbridge passes through Virginia, Maryland, and Washington, D.C.

The bridge's highly-contested plaque (once again) honors Confederate President Jefferson Davis.

The whole world in one water tank.

One of the only memorials dedicated to journalists who died in combat.

The tallest The Church of Jesus Christ of Latter-day Saints temple in the world soars above the Beltway.

A benevolent, 16-foot-tall river dragon lives on a suburban lawn.

Walk a trail through a historic Quaker town that outlawed slavery in 1777 and was a major waypoint on the Underground Railroad.

Giant acorn-shaped 19th century gazebo from which suburban Washingtonians gazed upon the original "silver" spring.

Remains of a historic fountain that was mysteriously lost in the demolition of a D.C. traffic circle.

A star fort along the C&O Canal in western Maryland that protected America in three wars.

A monumental statue of RCA's mascot now sits atop a historical society roof after a life of moving around.

An FDR-era tuberculosis sanatorium has stood abandoned in the suburbs of the U.S. capital for over 30 years.

This fort down the Potomac from Washington, D.C. was once the only defensive fort protecting the capital.