1912-baist-detail-Union-&-9th-web June 5, 2016 500 × 600 Seattle Now & Then: Florists’ Row at 9th & Union The unique intersection (right-center) of 9th Avenue and Union Street in a detail from the 1912 Baist Real Estate Map. Eighth Ave., on the left, is now a viaduct falling through the Convention Center on its span from Seneca Street to Pike Street.