Staircase winds down the side of Telegraph Hill through gardens, wild parrots flying overhead.

A sacred site for Native Americans surveyed by George Washington and owned by both King George III and Thomas Jefferson.

Quite simply the largest tree in the world (by volume).

The second-largest cave chamber in the world was discovered in 1898 by a 16-year-old and a friend known as "Pothead."

This frequently-photographed waterfall takes only a short hike to visit.

Possibly the most beautiful carillon in the world, set atop Iron Mountain in Florida.

The first declared National Monument in the United States.

This shop for all your super spy needs hides an educational secret.

There is no trying to fall in love with this Star Wars fountain, you just do or do not.

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

An enormous, inside-out glass globe built in 1935.

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

The legendary building that needed ghostly approval before being built.

A collection of vintage liaison aircraft kept in flying condition and on display at an airfield in San Antonio.

One of only two pod-shaped homes designed by Frank Lloyd Wright.