Strange red rock formations that have been attributed to a higher power for hundreds of years.

An experimental, automotive replica of Stonehenge.

America's original house of worship for Spiritualism, the religious movement based on communing with the dead.

One of the now-less-hidden floral gems of the "Emerald Necklace."

19th-century operating theatre in which the use of ether was first demonstrated - plus, a skeleton and a mummy!

This Boston medical museum features the skull of the famous medical case of Phineas Gage.

Oldest unrestored plantation house in America that is open to the public.

This once-private estate is now a dreamy, meditative garden that's open to the public.

American artist J. Alden Weir purchased this 60-acre estate for $10 and a painting.

This abandoned psychiatric hospital once housed more than 4,000 patients in the middle of a quaint New England town.

The semi-reclaimed ruins of this canal were once part of an ambitious plan to reroute the mighty potomac.

One tiny triangular park commemorates the victims of a yellow fever epidemic—many of whom are buried right below the grass.

A genuine Tudor manor transported piece by piece from England.

The elevator hidden in a smokestack on Roosevelt's yacht now serves as a monument to the former president.

This 1830s store is believed to be the site of Harriet Tubman's first stand.

The skeletal white beams stand as a monument to religious dissent.

A home built with marble tombstones from the graves of 2,200 Union soldiers buried in a Virginia cemetery.

Under a playground is a little-known sealed train tunnel that likely contains the bodies of workers trapped by cave-ins.

This historic, one-acre island is the only legal place to camp in the city of Richmond.

This museum devoted to the gothic author holds such interesting ephemera as his socks and walking stick.

America's first public mental health facility.

A vast collection of everyday items amassed by one man.

The childhood home of the famous general's mother is now a small, walled garden.

A monument to a Native American leader who was known for never breaking a promise and met his end after signing a deal with white settlers.