800 Fifth Avenue is a 166 m skyscraper in Seattle, in the U.S. state of Washington. It was constructed from 1979 to 1981 and has 42 floors. It is the tenth-tallest building in Seattle and was designed by 3D/International. The building was previously known as Bank of America Fifth Avenue Plaza when its naming rights were held by the Bank of America. It was originally built for Seafirst Bank, which was acquired by the Bank of America. In April 2014, its name was changed to 800 Fifth Avenue. The building was acquired by EQ Office in 2019. It underwent an interior renovation in 2022 that was designed by Olson Kundig to create more lobby space and a public garden.

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