This massive redwood tree has a hole in the base big enough to drive through.

One of the most scenic stretches of road in America winds between some of the country's oldest trees.

Two mammoth statues inspired by equally tall tales lure tourists to this roadside attraction.

This natural marble cave is one of only five national monuments in Oregon.

This lighthouse has been guiding shipping into the Golden Gate since before the American Civil War.

A historic lighthouse steeped in rumors of ghost and pirate stories.

A monument commemorating the discoverer of radio astronomy.

A pig barn converted into one of the most eclectic residences in Nantucket.

The largest body of water in Massachusetts annihilated four small towns just to slake Boston's thirst.

This delicate museum is devoted to the art and industry that once supported Cape Cod's oldest town.

Two gushing waterfalls of hot spring water within a block of each other.

Hidden for 165 years inside a building designed by Thomas Jefferson are the remains of what may be America's first educational chemistry lab.

Thomas Jefferson's estate is home to hundreds of varieties of historic fruits and vegetables.

This museum-within-a-museum pays tribute to "The World's Most Experienced Airline."

Abandoned power station once home to a squatter community, now being developed into an arts center.

The lasting remains of the region's once booming cement industry.

This small park features a monumental fountain wall, providing a great photo opportunity in the middle of Houston.

The National Park Service’s best-kept secret with views that rival any in D.C.

The remains of the medieval wall that once surrounded Paris with ties to the construction of the Louvre.

Once America's longest-manned military fort, now an abandoned hulk.

The third-tallest lighthouse in the United States stands as a reminder of Atlantic City's early days.

"A hideous albatross in the Hudson River Valley."

A well-preserved example of an early industrial operation in the northeastern United States.

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