A horde of stray cats rule in this secluded Parisian cemetery under a bridge.

Abandoned railway line circling the city of Paris.

This massive library holds what was once the largest book collection in the world.

France's most famous cemetery, with some of its most curious tombs.

The industrial architecture honors the laborers who brought the Exposition Universelle of 1900 to life.

For more than a century, revolutionary graffiti has marked the wall of a Parisian church.

This 18th-century sundial was designed to calculate the date of Easter each year.

This restored house is like a time capsule of the president's unconventional inauguration.

An abandoned cemetery lies in ruins as the surrounding forest swallows it whole.

Huge masonic hall in Philadelphia with lavishly themed rooms.

Beautiful views of the surrounding hills and birds of prey can be found at this sanctuary.

A beloved horticultural oasis on the grounds of a wealthy family's former estate.

Narrow gorges and deep pools created by long-ago glaciers.

Believed to be the birthplace of the United States Marine Corps.

A converted hangar displays dozens of helicopters, from a famous 1943 rescue chopper to several autogyros.

This Civil War monument was designed by an eccentric architect and Gettysburg veteran.

While seemingly a cruel joke, this bench actually honors an esteemed member of the community who passed away in 2006.

A sycamore tree grown from seeds that traveled to the moon.

This covered bridge was used by both Union and Confederate troops during the Battle of Gettysburg in 1863.

This large stone residence served as a field hospital during the Battle of Gettysburg between stints as a tavern.

Venture into the past with an unlisted exhibit hall featuring extinct birds.

This fine arts hall honors the mastermind behind our beloved creepy and kooky Addams Family.

This is the spot where the bloodiest battle in the American Civil War may have started.

This overlooked courtyard and museum celebrate Benjamin Franklin's life and achievements.