The massive machine creates cracking displays of indoor lightning.

As state highpoints go, this spot is one of the lowest, but for years it was also the hardest to climb.

No one knows who painted this mysterious mural in a Penn State basement.

Near-constant high winds deform the trees on Spruce Knob, the highest point in West Virginia.

Pennsylvania's highest point is spotted with boulders which were pushed to the surface by nothing but cold.

The highest point in Maryland is only accessible by hiking through another state.

The largest hot spring in the United States is, as the name suggests, a stunning show of natural color.

A beautiful geyser under environmental threat.

One of nature's most well-scheduled phenomenons resides in Wyoming's Yellowstone National Park.

This bridge was the birthplace of a unit of measurement based on a fraternity joke.

Berthed at the Charlestown Navy Yard in Boston, "Old Ironsides" is the oldest commissioned warship still afloat.

Historic Hull Street was actually the first street with a proper name in the Boston area.

The site of Paul Revere's historic two lantern warning.

Narrowest house in Boston.

Macabre headstones carved with winged skulls, dancing skeletons, and pithy reminders of impending death.

What was once a true peninsula has now been filled in, causing the water to recede and leaving many streetside "waterfronts" and landlocked "islands."

The American Revolution was galvanized into serious action due to the tragic clash with British soldiers that occurred at this location.

An interesting decoration on this historic site, this weathervane comes with as many legends as it does questions.

A former waterfront market is now in the center of town due to some interesting Boston engineering.

The celebrated eyesore created by starry-eyed sweethearts.

The prototype for all Nazi concentration camps.

Daily jousts and dancing barrel makers in Munich's mechanical clock.

A phenomenal assembly of pueblos in New Mexico is the most complete example of ancient ruins north of the border.

A toxic ghost town sitting atop a massive coal fire.