These trees are living witnesses to events that inspired poet Walt Whitman’s service during the American Civil War.

The Virginia home of one of the signers of the Declaration of Independence is being preserved with a unique glass facade.

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

This once-palatial plantation may have been the site where a draft of the Declaration of Independence was written.

The last of Philadelphia's wood-paved streets is now a landmark of terrible engineering.

The oldest surviving presidential residence in the United States.

This charming colonial alleyway is one of the oldest continuously used residential streets in the U.S.

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

It would take 35 firetrucks to fill this enormous glacial pothole.

The graffitied ruins stand hidden within the Pennsylvania woods.

Collection of trolley cars in the woods represent one man's attempt to preserve transportation history.

Over 100 concrete munitions bunkers are all that remain of a Pennsylvanian village seized by the US government.

Eccentric concrete mansion and museum designed and built by hand from the inside out.

Once the "Eighth Wonder of the World," this iron railroad bridge was decimated by a tornado.

These beautiful ruins deep in the Pennsylvania woods are thought to have been a ski lodge or a speakeasy, but no one really knows.

An abandoned stretch of highway, deteriorating next to the operational one.

Frank Lloyd Wright's most iconic home dangles over a Pennsylvania waterfall.

A glittering Thai Buddhist temple in suburban Pennsylvania.

This stone tower marks a lookout point over the historic Washington Crossing, and maybe some buried treasure.

Its vintage camera collection gives a snapshot of the past as viewed through a photographic lens.

This little-known Revolutionary War fort is supposedly haunted by the ghosts of its past.

A failed piece of Orientalism has become the proud symbol of a community.

A mine fire has been burning under the deserted town since 1962, but this church is still going strong.

A modern ghost town whose inhabitants were driven away by the growth of nuclear power.