The largest self-built castle in the U.S., six decades in the making.

The ancient dwellings of the Puebloans, located in the cliffs of majestic mesas.

Crystal clear lake with a shoreline of travertine located in a Colorado canyon.

Wondrous sandstone hoodoos where Native Americans collected clay for pottery, 9,000 years ago.

In an alley not far from where two great highways meet, byways of a very different sort are honored.

The large rock formation where the Shawnee prophet Tenskwatawa stood and encouraged his warriors during the Battle of Tippecanoe.

A large collection of motorbikes with some impressive gems.

Part of a worldwide art project, this mysterious semicircle of concrete shapes holds the pieces of a larger story.

One tree's homage to soles past and present.

The only freestanding table rock formation east of the Mississippi.

This candy shop has been serving up sweets to the Louisville area since the 1850s.

Display that gathers the basic elements of the universe in one convenient location.

A 30-year-old Sycamore tree grown from a seed taken to the moon and back.

Lions and tigers and leopards, servals, pumas, bobcats, lynxes, and ocelots... oh my!

Symbolic attempt to overcome the issues of life.

The longest navigable underground river in the United States is home to countless blind and albino animals.

A hidden network of subterranean passageways lies tangled beneath Indianapolis' bustling City Market.

This 3,500 pound obelisk was constructed with more than 1,000 reclaimed guns.

The often-overlooked ruins of one of the first buildings designed by famous landscape architect Frederick Olmsted.

This massive boulder is inscribed with the story of a sensational hostage negotiation dating back to Colonial times.

One of the last remaining World War II Victory Gardens in the U.S. is quietly growing across from Fenway Park.

One of the most scenic falls in Massachusetts has a history of death and grim legend.

America's greatest forgotten garden and the former stomping grounds of Son of Sam.

This dilapidated castle-like structure overlooks the Hudson River at one of its widest points and was once home to nuns.