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

A "Texanic" (gigantic Texas) collection of Art Deco architecture at Dallas' historic Fair Park.

This strategically-placed fountain creates the magnificent illusion of mustangs galloping across a river.

A 400-foot-tall tall map of Chicago makes this once-ignored building stand out.

The unluckiest U-boat in the entire German fleet is now on display in a Chicago museum.

At Chicago's revered Field Museum, visitors are invited to learn about and literally explore DNA.

Years of archaeology, just chillin' by the water cooler.

A registered historic landmark shrouded in unsettling local legends.

One of the largest collections of intact Victorian-era waterworks equipment in the world.

This extraordinary Depression-era expenditure was modeled after a postcard of a Mediterranean hotel.

Half-sized replica of the Leaning Tower of Pisa built to honor Galileo.

An unusual, super-sized grocery adventure awaits in an Ohio suburb.

Walk in the footsteps of the famed astronaut at Purdue University.

Sunset-colored dunes of volcanic ash make taking a poor photo impossible.

The largest hot spring in the United States is, as the name suggests, a stunning show of natural color.

A beautiful geyser under environmental threat.

An architect's childhood fantasy treehouse made real.

This Yellowstone geyser may not shoot as high as the nearby Old Faithful, but it erupts for considerably longer.

Stroll through a wonderland of stupendous moss-covered trees.

A vertically floating hemlock controls the waves and weather at Crater Lake.

The deepest lake in the United States, and once the site of epic destruction that lives on in legends.

The first declared National Monument in the United States.

Strange red rock formations that have been attributed to a higher power for hundreds of years.

These faux-cliff dwellings allow visitors to climb around on a replica archaeological site.