The sounds of the world's largest fully functioning pipe organ dazzle shoppers at a Philadelphia Macy's.

This elaborate towering structure was once famed for its revolutionary height.

The first American department store, and home to the largest operating musical instrument in the world.

Dr Barnes' $25 billion private collection of art and arboretum.

Huge masonic hall in Philadelphia with lavishly themed rooms.

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

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

The headquarters of a secretive order is also a beautifully-designed park.

A museum documents the development of the invention that tamed the Wild West.

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

A fantastic array of trays and cables once whisked books over to the Capitol at 600 feet per minute.

Members of Congress have traveled between the buildings on Capitol Hill for a century hidden from tourists, press, and storm clouds.

100 years later, they're still down there.

The actual model from the original "Star Trek" series is now on display at the National Air and Space Museum.

Berkeley Hot Springs presents to you "the only outdoor monument to presidential bathing."

Exact replica of the ancient monument, but much, much lighter.

Forget Hollywood, one of the biggest stars in the world can be found in Roanoke, Virginia.

A sacred site for Native Americans surveyed by George Washington and owned by both King George III and Thomas Jefferson.

The largest earthwork effigy in the world.

This recently rediscovered Civil War-era submarine was the first to ever sink an enemy ship.

Charleston's historic city jail once held everyone from pirates to Civil War POWs.

Paths are maintained, but trees have taken over plots.

South Carolina's last remaining slavery auction house is now a museum devoted to its own tragic history.

This tower in a small Polish village uses the power of a sacred bell to ward off mischievous weather spirits.