It’s the stuff of urban legends: Two guys with no community organizing or fundraising experience, Joshua David and Robert Hammond, save a 1.5-mile stretch of abandoned railway from demolition, and transform it into urban marvel known far beyond its home of Manhattan. Two stories above ground level and slicing through a forest of tall buildings on New York’s West Side, the High Line, as it’s called, isn't just a breathtaking “park in the sky.” It's spurred unprecedented economic growth in its surrounding neighborhood—in excess of $2 billion in new investment, according to city estimates.