Anza Borrego Desert State Park

The sweeping 650,000-acre Anza-Borrego Desert State Park, the largest state park in California, lies mostly within San Diego County (in fact it makes up more than 20% of the county). A sense of timelessness pervades this landscape -- the desert is home to fossils and rocks dating from 540 million years ago; human beings arrived about 12,000 years ago. The terrain ranges in elevation from 15 to 6,100 feet above sea level. It incorporates dry lake beds, sandstone canyons, granite mountains, palm groves fed by year-round springs, and more than 600 kinds of desert plants. After the winter rains, thousands of wildflowers burst into bloom, transforming the desert into a brilliant palette of pink, lavender, red, orange, and yellow. The giant ocotillo bushes flower extravagantly, hummingbirds fill the air, and an occasional migratory bird stops off en route to the Salton Sea. The park got its name from the rare bighorn sheep, or borrego, which can sometimes be spotted navigating rocky hillsides. The other half of the name comes from Spanish army officer Juan Bautista de Anza, who from 1774 to 1775 led back-to-back expeditions (including one with more than 200 men, women, and children, plus livestock), through the desert from the Gulf of Mexico to the California coast. Following his second journey to the ocean, he made his way north, laying the groundwork for the presidio and mission that would become the city of San Francisco.

Many people visit the area with little interest in the flora and fauna -- they're here to relax and sun themselves in tiny Borrego Springs, a town surrounded by the state park. It is, however, somewhat remote, and its supporters proudly proclaim that Borrego Springs is and will remain what Palm Springs used to be: a small, charming resort community with more empty lots than built ones. Yes, there is a golf resort, some chic fairway-view homes, and a regular influx of vacationers, but it's still plenty funky. One of the valley's unusual sights is scattered patches of tall, lush palm tree groves, perfectly square in shape: Borrego Springs's tree farms are a major source of landscaping trees for San Diego and surrounding counties.

When planning a trip here, keep in mind that temperatures rise to as high as 125°F (52°C) in July and August. Winter days are very comfortable, with temperatures averaging around 70°F (21°C) December through January, but nighttime temps can drop to freezing. Hypothermia is as big a killer out here as the heat.