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

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

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

Two thousand artifacts from around the world collected by one woman who loved to travel.

An enormous, inside-out glass globe built in 1935.

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

This lovely picnic spot featuring thunderous jet landings is an aircraft spotter’s dream.

This isn't your average roadway—it's actually a National Park and a transportation pioneer.

An organ located deep within a cave, whose "pipes" are the geological features of the cave itself.

The only recreation of William Shakespeare's indoor playhouse.

The ruins of this Thomas-Jefferson-designed mansion have been left to crumble since the Christmas Day they burnt down.

Hidden for 165 years inside a building designed by Thomas Jefferson are the remains of what may be America's first educational chemistry lab.

Edgar Allan Poe's old dorm is now a shrine to the author's legacy.