A semi-scholarly approach to sex.

A beautiful and abandoned New York subway station from 1904, complete with chandelier.

Once decrepit and slated for demolition, now one of the longest pedestrian bridges in the world.

Knoxville’s architectural icon was the symbol of the 1982 World’s Fair, even catching the googly eye of Bart Simpson.

This historic train station has been converted to a locomotive themed hotel.

This funicular railway rumbles along for a mile up the nearly vertical face of Chattanooga’s Lookout Mountain.

A recreation of the doomed ocean liner in the middle of the Smoky Mountains.

Mile-long cave system near Great Smoky Mountains.

The mysterious wonder of an underground waterfall is illuminated by multicolored lights.

Wild lights and sound effects turn a walk through some caves into an eye-popping 1960s tourist attraction.

Enormous lake at the bottom of a unique cave system.

Holding multiple historical boats and an entire 19th century village, this New England attraction is the largest maritime museum in the world.

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

Built to bless whalers before their voyages, this Massachusetts church now features a ship-shaped pulpit.

Hill-like structures formed by glaciers and sandy spits of land.

This donated headstone marks the grave of a pair of elderly women who were mysteriously murdered.

Solar powered Spectacle Island features all-green facilities.

A careful eye can find hundreds of dinosaur tracks running along the Connecticut River.

One of two lighted lanterns hung in the church belfry on the eve of the Revolutionary War to warn that the British were on their way.

Located in a beautifully restored ice house, this museum is the result of decades of hard work and devotion to the craft of plumbing.

Artifacts of whaling, with both its perils and adventure, are housed in this museum in a former candle factory.

Located just behind a quiet residential neighborhood, this is ground zero for the Salem witchcraft hysteria of 1692.

A steampunk wonderland that preserves America's history of industrial innovation.

One of America's most historic homes also holds a startling literary legacy.