One of the most extensive and well-preserved collections of dinosaur footprints in North America.

The longest-covered bridge in the state of Maryland.

A desert settlement founded and later abandoned by Hawaiian members of the Church of Jesus Christ of Latter-day Saints in Utah's Skull Valley.

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

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

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

A rural colonial settlement that contains the remains of a store and cooper.

One of the oldest log cabins in America is one of the last of its kind this historic Swedish dwelling remains a piece of living history.

The C. A. Nothnagle Log House stands as the oldest surviving log cabin in the United States, offering a remarkable glimpse into America's colonial past.

North America's oldest quarantine facility was built in response to Philadelphia's 1793 yellow fever outbreak.

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

The first marker along the famous boundary.

An award-winning children’s garden enchants visitors at the intersection of natural beauty and fairy tales.

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

The meeting of the northwestern corner of Delaware, the northeastern corner of Maryland, and the southern edge of Pennsylvania.

This palatial botanical garden is home to one of the largest pipe organs ever installed in a private residence, and a piece of Wood's cycad.

Descendants of this colonial Pennsylvania family still travel from far and wide to visit the 300-year-old home of their Quaker ancestors.

These ruins of an octagonal stone school that was later used as an A.U.M.P. church exemplify a popular school design from the 1830s.

The smallest and oldest covered bridge in Delaware.

The longest covered bridge in Delaware.

The second oldest and longest of Delaware's three covered bridges.

Enchanting gardens surround a derelict mansion, all hidden in plain sight behind a stone wall.

This splendid Versailles-inspired mansion has the largest French-style formal gardens in North America.

A late sculptor's last project was to turn this abandoned cement factory into a castle-themed amusement park.