One of the oldest theaters in Australia, it's also said to be haunted by a performer who died on stage.

Come for the flowers, stay for the bats!

Nine limestone rock stacks on Australia's "Shipwreck Coast."

Built over an abandoned train yard, this hidden gem is full of winding paths and offers gorgeous views of Sydney Harbour.

This pre-Hispanic apartment complex also includes ancestral paintings that point to its military past.

Dating back to the second century, vestiges of prehispanic mural paintings are found in this underground palace.

An Aztec temple, the largest man-made pyramid in the world, sits buried in earth with a Spanish church set on top.

The historic home still shows the scars from a little run-in with the British in 1813.

WWII-era bunkers are hidden under the beaches of this picturesque park, which is still scattered with wartime watchtowers. .

Erected in 1697 this Philadelphia bridge is the oldest surviving roadway bridge and perhaps the oldest stone bridge in the United States.

America's smallest national park site is the former residence of exiled Polish national hero Thaddeus Kosciuszko.

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

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

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

A tour de force of a fountain, memorializing a man who loved fountains more than anything else.

A daily replay of the experiment that proved the rotation of the Earth.

Yo, Adrian!

The highest point in Delaware is located under a trailer so this marker across the street will have to do.

The Dover International Speedway is home to a towering, concrete-skinned, racecar-hungry behemoth.

A scenic fort on the harbor protected Philadelphia from an attack that never came.

These lush botanical gardens employ the most purrfect pest control force.

The oldest farmer's market in America is so ancient it was approved by the King of England.

These tourist trap caverns are said to be the former home of a legendary Pennsylvania Hermit.

The romance of early commercial flight still fills this Art Deco destination.