Hidden behind a Target are pillows of cooled lava that formed at the bottom of a deep lake in the Mesozoic Era.

A human attendant once directed car traffic from this structure before automated stoplights.

Now home to hardy plants, these sand and gravel dunes once held back a massive prehistoric lake.

The gravestone of an eccentric Connecticut doctor features dinosaur tracks and a pair of fossil tree casts.

This petite park lets visitors see and touch examples of fossilized dinosaur tracks.

This historic railway museum may have lost its passengers but not its love for trains.

A castle inspired by medieval architecture is hidden in the woods of Connecticut.

Memorial to one of the most fatal fires in both circus and U.S. history.

Ruins of a historic medical facility sits eerily by the water.

This small-town Connecticut restaurant gives each diner a free book from its vast library.

The final resting place of one member of the Amistad slave revolt who never made it back home.

Public outcry led to this bridge's unique character which celebrates a giant frog battle and also sewing.

The author of Uncle Tom's Cabin was neighbors with Mark Twain while living in this Connecticut home.

Glacial erratic or man-made dolmen? It probably wasn't druids.

Mansion and shopping center used in the 1975 film "The Stepford Wives."

At this farm in upstate New York, the former president plotted his reelection campaign.

A beacon atop a downtown building provides Bostonians with weather forecasts and baseball news.

Home of the only civilian casualty at the Battle of Gettysburg.

The little-known final resting place of one of America's greatest writers.

A statue commemorating a 16-year old girl's nighttime ride to raise a militia against attacking British troops.

This statue commemorates the importance of hat manufacturing to Danbury, once known as the "Hat City of the World."

The oldest continuously occupied public building in the United States.

These unassuming lighthouses have seen the first reading of the Pledge of Allegiance, the first wireless transmission, and more than one mystery.

The sea urchin sculpture is an unusual commemoration of a New England town's seafaring history.