One of the most scenic stretches of road in America winds between some of the country's oldest trees.

This massive redwood tree has a hole in the base big enough to drive through.

This Taoist temple is the oldest continuously used Chinese temple in California.

This ultra-modern California span is actually a titanic solar clock in disguise built by famed architect Santiago Calatrava.

The fossilized remains of ancient California redwoods.

California's own medieval Italian castle, authentic down to the 300-year-old iron maiden in the dungeon.

The largest drain hole in the world.

The world’s largest truck stop includes a barber shop, chiropractor, and a huge museum with antique trucks.

An unlikely Transcendental Meditation haven in the American Heartland built around the ancient Vedic principles of balance and harmony.

One of just a few cities in the world to base their center of government on an island. Others: Paris and Osaka.

A place of great reverence for Trekkies everywhere, a hero's future birthplace.

The last holdout of a pre-Civil War rebel who took the matter of slavery into his own hands.

Captain John Smith thought these cliffs were amazing in 1608 but sharks thought so 20 million years before him.

Once America's tallest structure, now a Baltimore landmark.

The trials and tribulations of marking Poe's grave.

A museum dedicated to exhibiting remarkable outsider art.

At Washington's Dulles Airport is a satellite museum (no pun intended) with three quarters of a million square feet of aircraft history.

This fort down the Potomac from Washington, D.C. was once the only defensive fort protecting the capital.

The tallest The Church of Jesus Christ of Latter-day Saints temple in the world soars above the Beltway.

Once home to seven different roller coasters, Glen Echo has undergone many transformations since its founding in 1891.

An astounding collection of medical specimens, including bits of President Lincoln.

America's first federal monument.

This stately building in Alexandria, Virginia was built by Freemasons to honor one of their most famous members.

An original apothecary from 1792.