The only surviving fragment of the lost Narragansett Pier Casino.

One of the oldest carousels in the United States is still running in the coastal village of Watch Hill.

One of the first intercontinental ballistic missile sites in the United States.

The highest point in New Jersey is marked by a massive, if simply named, obelisk.

Inspiring Herman Melville and Henry David Thoreau, Mount Greylock in western Massachusetts is the highest point in the state at 3,491 feet above sea level.

The spot in the Mile-High City that's exactly 5,280 feet above sea level (at least for now).

The unusual patterns in this rock formation result from two distinct modes of weathering.

A tunnel with windows, so you don't miss out on the impressive views.

While most wind tunnels test scale models, the "Cave of Winds" was large enough for actual airplanes.

The only one of New Hampshire's original 14 World War II watchtowers to survive in near-original condition.

Inside houses a vast collection of military aircraft and missiles spanning the ages.

This classic steam-powered train takes tourists on a nostalgic trip around the Connecticut River Valley.

Dedicated to the history of the 1,000 nuclear missiles that once covered the Great Plains.

This historic address is home to the beloved ball and is an almost totally empty building among the most expensive real estate in the world.

Beautiful mosaics cover the first stations opened on New York City's newest subway line.

The walls of America's oldest masonry fort famously "swallowed" cannonballs.

Unicorns, elephants, and bears, oh my!

The romance of early commercial flight still fills this Art Deco destination.

The world-record holder for the longest bridge stretching continuously over water.

This iconic 1958 tower welcomes air travelers to Tucson with neon-lit letters and architectural style.

A monument to the one-armed geologist who led the first documented expeditions through the Grand Canyon.

This massive tea kettle was once a promotional stunt for the Oriental Teashop.

The enormous 250-room Vanderbilt mansion conceals hidden doors and secret passageways.

The rough and tumble president's childhood home displays the shirt he was once shot in and the speech that saved him.