Jane Jacobs, the urban activist whose influential book The Death and Life of Great American Cities reshaped thinking about urban communities, died overnight in Toronto. Jacobs, who lived in Canada since 1968, faced down NYC Parks Commissioner Robert Moses, arguably the most powerful man in the city at the time, in the 1960s, most famously stopping an expressway from being constructed downtown.
Wikipedia on Jacobs. A 2004 Talk of the Town New Yorker piece about a visit to NYC (she didn't think anything should happen at Ground Zero for 15-20 years). The Project for Public Spaces has a good summary of her perspectives. And Treehugger suggests that we should plant trees in her memory.