Tens of thousands of acres later, a group backed by Silicon Valley's wealthiest says it's done buying up land in northern California for its walkable, utopian city. Flannery Associates has been grabbing plots of land in Solano County, about 60 miles from San Francisco, for the past five years. The company has spent about $800 million to purchase tens of thousands of acres of farmland with the support of tech billionaires, including Marc Andreessen and Laurene Powell Jobs.