Abandoned Air Force base that has fallen into disrepair.

A world-class observatory in the California desert.

One of the largest trees of its kind in California.

North America's largest accredited model railroad museum.

An extraordinarily ornate museum in San Diego holds wondrous anthropological treasures.

The world's largest outdoor organ is played weekly by one of just two civic organists in the U.S.

This futuristic bridge is one of the longest self-anchored pedestrian bridges in the world.

The oldest standing structure in downtown San Diego.

A sculpture of the famous photograph stands on San Diego's "Greatest Generation Walk."

L. Frank Baum wrote part of the "Wizard of Oz" series in this wooden Victorian beach resort.

A blast from the past in central San Diego.

Go deep on these fascinating fish, and get a bonus lesson on the importance of marine conservation.

A dramatic coastline that’s home to a rare pine tree.

These unusual houses look like giant boats that washed ashore on a residential street.

The oldest structure in a beachside California city was built to serve eight students.

In all of the 29 years it was in operation, no prisoners ever escaped successfully... or so they claim.

A bit of retro transportation flair preserved in the world's largest department store.

Swarms of butterflies cannot compare to the awe inspired by the publicly-funded nakedness once displayed in this sunken garden.

A hidden courtyard houses early 20th-century plaster masterpieces.

Built for an exposition in 1915, these horticultural displays have stood the test of time.

The freeway that never was.

An inconspicuous footbridge beloved by San Diego locals.

In September 1974, a small group of athletes completed the first modern triathlon event in San Diego's Mission Bay.

A mosaic map made of over 100,000 tiles depicts the geological features and sea creatures that live along this San Diego beachside community.