High Quality Content by WIKIPEDIA articles! 1201 Third Avenue, formerly Washington Mutual Tower is the second tallest skyscraper in the downtown Seattle skyline. At 55 stories and 235.31 m (772.0 ft), it is the eighth tallest skyscraper on the West Coast. Developed by Wright Runstad Company, construction began in 1986 and finished in 1988. The building was designed by Kohn Pedersen Fox Associates and The McKinley Architects. The building was the world headquarters of the financial company Washington Mutual from the building`s opening until the company moved into the WaMu Center across the street in 2006.