The Ryerss mansion in Burholme Park now houses a community library and a museum filled with a trove of oddities from around the world.

The oldest surviving presidential residence in the United States.

This little-known collection holds everything from "Dracula" notes, to the manuscript of "Ulysses," to the forged works of Shakespeare.

A rare view of a preserved Victorian science museum.

Tour the dark and beloved poet's former cobwebbed basement, which may have inspired "The Black Cat."

Philadelphia boasts one of the best — and most often overlooked — traditional Japanese gardens in North America.

America's most famous museum of medical oddities is home to the remains of Albert Einstein's brain.

World's first "penitentiary," meant to be humane, drove men insane.

Standing atop 2nd-century Roman ruins, this church is one of the oldest and most iconic in Old Cairo.

The massive cave church of Cairo's Zabbaleen community is one of the largest Christian churches in the Middle East.

An ancient instrument used to measure the waters of the Nile so Egyptian farmers would know whether to expect famine or flood.

The narrowest house in America is seven feet of pure spite.

An original apothecary from 1792.

The former home of elite checkers battles of the Capital Pool Checkers Club.

The first museum in the U.S. to address human rights issues in China.

One of the last mosaic tile facades found in the city.

The legacy of a wealthy executive and his wife, this little-known art museum features works by Picasso, Monet, Renoir, Cezanne, and more.

The National Park Service’s best-kept secret with views that rival any in D.C.

Once home to the largest photo service in the United States.

The "Key of Keys" for Washington, D.C. and the apocryphal landing place for the military campaign that started George Washington's career is now at the bottom of a well.

This Masonic lodge was the first major private building to be constructed in Washington, D.C. after the Civil War.

The ruined remains of a coal mining ghost town are hidden within the woods.

Considered by many to be a local landmark and treasure.

A pyramid commemorates the birthplace of James Buchanan, the 15th president of the United States