L.A.'s beaches are an iconic and integral part of Southern California, and getting some sand on the floor of your car is practically a requirement. Hugging the Santa Monica Bay in an arch, the desirable communities of Malibu, Santa Monica, and Venice move from ultrarich to ultracasual to bohemian. What they have in common, however, is cleaner air, mild temperatures, horrific traffic, and an emphasis on the fun in the sun beach-focused lifestyle.

Santa Monica —which, because of its liberal populace, has been dubbed the People's Republic of Santa Monica—is a pedestrian-friendly little city, about 8.3 square mi, with a dynamic population of artists and writers, entertainment folks, educators, and retired people, all attracted by the cooler, sometimes-foggy climate. Mature trees, Mediterranean-style architecture, and strict zoning have helped create a sense of place often missing from L.A.'s residential neighborhoods. This character comes with a price: real estate costs are astronomical.

Venice was a turn-of-the-20th-century fantasy that never quite came true. Abbot Kinney, a wealthy Los Angeles businessman, envisioned this little piece of real estate as a romantic replica of Venice, Italy. He developed an incredible 16 mi of canals, floated gondolas on them, and built scaled-down versions of the Doge's Palace and other Venetian landmarks. Some canals were rebuilt in 1996, but they don't reflect the old-world connection quite as well as they could.

Ever since Kinney first planned his project, it was plagued by ongoing engineering problems and drifted into disrepair. Today only a few small canals and bridges remain. On nearby Abbot Kinney Boulevard there's a wealth of design and home decor shops and chic cafés—plus great people-watching.

North of Santa Monica, up the Pacific Coast Highway, past rock slides, Rollerbladers, and cliffside estates, is Malibu. Home to blockbuster names like Spielberg, Hanks, and Streisand, this ecologically fragile 23-mi stretch of coastline can feel like a world of its own, with its slopes slipping dramatically into the ocean.

In the public imagination Malibu is synonymous with beaches and wealth—but in the past couple of years there's been some friction between these two signature elements. Some property owners, such as billionaire music producer David Geffen, have come under attack for blocking public access to the beaches in front of their homes. All beaches are technically public, though; if you stay below the mean high-tide mark you're in the clear.

And everyone is welcome (with reservations) to the reimagined yet still intimate seaside Getty Villa and its collection of Greek, Etruscan, and Roman art and artifacts.