The first declared National Monument in the United States.

A plaque marks the site directly below the mid-air detonation of the atomic bomb over Hiroshima.

The state's oldest continuously operating museum houses more than 5,000 Civil War artifacts.

A six-ton wedding present for the King of the Scots.

A grand Gothic Revival basilica with stained glass depictions of Montreal's religious history has only one soul resting in its crypt.

Ruined 11th century abbey built by King David I in Edinburgh, Scotland.

Oregon's unexpected high desert, displaying layers of time in a colorful show.

Ha Long Bay's "Cave of Surprises" houses a popular phallic rock formation.

Every equinox this Maya pyramid puts on a spooky ancient light show.

No telescopes, no power, no gift shop: The Observatory of Chichen Itza, one of the world's oldest observatories, takes astronomy back to basics.

A tiny piece of the Moon is embedded in this stained glass masterpiece.

These azure waters were thought to lead to the Mayan Underworld.

Paranormal activity on the great lakes.

A mysterious chasm in the heart of the ancient Roman Forum, the Lacus Curtius was once believed to be a gateway to hell.

The fifth-longest suspension bridge the world, connecting one Michigan peninsula to another.

This cemetery has graves dating back to the 17th century, including the city's oldest carved tombstone and an ominous cryptogram.

The "lovely red Vega" of the legendary record-settling pilot.

Home to three historic ships from the age of Vikings.

The land is home to swimming ponies and a legendary 18th-century treasure.

A sealed test tube said to hold Thomas Edison's dying breath was given to the inventor's friend and mentee, Henry Ford.

The only surviving prototype for Buckminster Fuller's house of the future.

This former rail stop in Utah was abandoned, repopulated by some nostalgic friends, and now is home to a single DIY aviator who lives in a hangar.

A massive Montreal stadium that has seen nothing but trouble since its inception.

Formerly known as National D-Day Museum, this collection commemorates the battles of Normandy and WWII.