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

This Roman arch marks the location of an ancient gate at one of the Seven Hills of Rome.

2300-year-old Roman road connecting the empire.

At the crypt of St. Mary of Eulogies and the Dead you are left alone to ponder mortality among piles of skulls.

The underground sanctuary of a mysterious ancient cult.

The yawning maw of this pagan visage is said to bite off the hands of liars.

The oldest lawn bowling club in the United States.

In all of the 29 years it was in operation, no prisoners ever escaped successfully... or so they claim.

The air force base preserves its scars from the Japanese attack on Pearl Harbor.

This black shoreline is made up of exploded lava particles.

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

Look closely and you’ll notice that the color changes a third of the way up the tower.

The remains of Martha, the last known passenger pigeon, serve as a tool to educate about conservation.

Rumor has it the uncarved lump behind the three famous suffragists is reserved for the first woman president.

An obscure public service from the U.S. government that redeems burnt, moldy, and soiled old greenbacks.

The actual model from the original "Star Trek" series is now on display at the National Air and Space Museum.

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

A late sculptor's last project was to turn this abandoned cement factory into a castle-themed amusement park.

What was once a presidential estate is now an exotic menagerie and home to the Budweiser Clydesdales.

Preserved "bog person" that is over 2,000 years old.

The world's longest known cave system.

The world's largest collection of the world's largest objects is in one small Illinois town.

When you visit his grave, be sure to rub the Great Emancipator's nose for good luck.

The Magic House provides a beautiful and creative environment for curious youngsters to get their knowledge on.