Welcome to the real Southern California—a peninsular playground of migrating whales, tony resorts, and the continent's last remaining undeveloped beaches. Susan Hack dives in

My journey across Baja California coincides with an age-old cycle: the arrival of thousands of gray whales in the Pacific inlets where they breed and give birth. On a windless January night, I hear their misty exhalations carrying across Laguna San Ignacio to my tiny, stilted cabin perched in a pool of moonlight between salt marsh and mangrove forest. Two hours by taxi from the nearest electrified town, which gets its power from an active volcano, I am having a Magical Realism moment. The sound of whales breathing fills the space between sea and sky, and images from my trip swirl around me: marine turtles painted high above the ocean on a desolate canyon rim; mummified puffer fish; a graveyard of ruined grand pianos. After the resort corridor of Los Cabos, Baja's desert heart is a gift, reminding me that the world was, and is, miraculous.

Part of Mexico, Baja (Spanish for "lower") is the original California, an eight-hundred-mile spine of mountains and shifting desert biomes pinched between the dark-blue Pacific and the turquoise Sea of Cortés. Below the U.S.-Mexican border and the triangle formed by the towns of Ensenada, Mexicali, and Tijuana, most of the peninsula consists of wilderness punctuated by three-hundred-year-old Catholic missions, abandoned mining concessions, tiny communities of goat ranchers and subsistence fishermen, and North America's last remaining undeveloped beaches. Despite the construction of a 1,054-mile transpeninsular highway in the 1970s and '80s, less than three percent of the coastline is accessible. Paved roads remain so scarce that many ranchers still travel on muleback along trails cut by missionaries in the eighteenth century.

Ever since Hernán Cortés crossed his eponymous sea in 1535 to what he thought was an island filled with Amazonians and gold, Baja has held out the promise of riches to men with big plans. The latest visionary is Mexican president Vicente Fox, who wants to build twenty-seven new marinas to entice tens of thousands of American yacht owners to cruise south from California into the Sea of Cortés and down the coast of the Mexican mainland. Fox delegated his plan—dubbed the Escalera Nautica, or Nautical Staircase—to FONATUR, the state tourism organization behind Cancún's unrestrained development.

Seeking gold in the form of direct foreign investment, the Mexican government in the 1990s skirted a provision of the 1917 constitution barring foreigners from buying seaside property. The law now permits ownership through Mexican banks, which hold the land in trust for foreign beneficiaries. That, plus the privatization of agricultural collectives, has put vast tracts of prime beachfront up for grabs. The northern Baja town of Rosarito, where Pacific-view houses cost less than $150,000, has turned into a commuter suburb for Americans working in San Diego. "Beach Lots for Sale" signs now surround the eighteenth-century mission town of Todos Santos, on the Tropic of Cancer, fifty miles north of land's end. A hamlet of five thousand, this longtime artist and surfer hideaway has lately sprouted kitschy hotels and tourist gimcrackery and may soon have its first golf course.