The maximum security facility was once thought to have "the bloodiest 47 acres in America."

In the St. Francois Mountains in the Ozarks at 1,772 feet above sea level, Taum Sauk Mountain is the highest (and possibly oldest) peak in Missouri.

One of the world’s largest collections of petroglyphs records 2,000 years of human activity.

A dozen U.S. presidents have stayed at the historic resort, which was known as James Buchanan’s “Summer White House” from 1857-1861.

The slate extracted from these Pennsylvania quarries was once hailed as the finest in the world.

The singer, actor, and activist lived here during his final years, and now it’s a museum dedicated to his legacy.

One Pittsburgh musician's decades-in-the-making memorabilia collection is on display at this rock-n-roll curio shop.

The final resting place of the Hollywood star who came to a tragic end.

Hundreds of protractors affixed to surfaces all over the city.

The only geyser in the state of Pennsylvania is caused by pressure from an abandoned coal mine outside of the ghost town Centralia.

A larger-than-life statue of America's favorite sundae marks the place it was invented.

The longest living non-clonal organisms on Earth.

Around half a million years ago, these magnificent columnar basalt cliffs were formed from cooling lava.

Miraculous tree that seems to sprout out of solid rock.

The first declared National Monument in the United States.

The oldest liquor store in the country is a model of resilience and mischief.

The only free-standing, vertical sundial in the US was keeping standard time before it was even invented.

A museum of the dime museum that features weird entertainments of yesteryear, from feejee mermaids to flea circuses.

One woman’s obsession gave birth to this lovely oddity at the Boston Public Library.

At the supposed instruction of Ben Franklin and Socrates, a Spiritualist believer intended to birth a mechanical messiah here.

An old trolley bridge was converted into a breathtaking garden bursting with colorful flowers.

Narrowest house in Boston.

House of vintage taxidermy and Steampunk sculptures in a quiet Pittsburgh neighborhood.

A park and memorial dedicated to the victims of the deadliest school massacre in American history.