The new $500 million headquarters for The Bill and Melinda Gates Foundation broke ground today on lower Queen Anne. The foundation headquarters take up an entire city block, across the street from the Seattle Center and his Microsoft buddy Paul Allen's pet project, the EMP. The planned campus will be 90,000 square feet and include offices for 1,200 employees as well as an interactive museum. Sadly there is no word if there will be a Batman-style signal for Bill Gates and the foundation. (A new economy is struggling? A library needs new computers? You want to talk about health care in Africa? Just flash the Gates Foundation signal!) The Gates foundation hopes to move into their new headquarters, with or without our super hero signal idea, in 2010.