In 2002, Orange County voters turned voted down a new international airport for Southern California. Instead, they agreed to turn the El Toro Marine Base into what's called "the Orange County Great Park." The federal government sold 3700 acres to the Lennar Development Corporation to build homes, businesses and a golf course on part of the land. Lennar gave 1300 acres to the City of Irvine for the Great Park. Through the Great Park Corporation, seven internationally known design firms were then asked for proposals and told not to worry about the budget. This week, they'll make official presentations of their plans, which include lakes, rowing canals, marshlands, monorails and hot-air balloon rides. We look at this unprecedented opportunity for public space and private profit.