Giant, natural amphitheaters made of delicate geological formations called "hoodoos."

This massive stained-glass masterpiece is thought to be the largest Tiffany dome in existence.

This bridge was constructed from the remains of the first Ferris wheel.

This midcentury chapel is a bold architectural statement and a symbol of Indiana's Lutheran heritage.

This large Sitka spruce that appears to be floating in mid-air, has defied logic for years.

A walk through the historic city center, under the streets of Seattle.

After a short-lived attempt to bring America in line with the rest of the world, this road was left in metric.

America's only nuclear missile silo open to the public.

Some of the tallest ancient American ruins continue to inspire awe and curiosity.

The unusual burial monument of Arizona's first governor.

Once a year, at exactly 11:11 a.m., this monument comes to life.

This Arizona observatory is famous for investigations into Martian life, and as the place humans first spotted Pluto.

A replica of the flagpole that gave a frontier town its name.

Ancient pueblos built into the base of a natural canyon wall.

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.

This isolated outpost was once the only place to cross the Colorado River for hundreds of miles.

Most-visited and most-photographed slot canyon in the American Southwest.

Dramatic river bend surrounds a natural red-rocked pedestal.