South Lake Union - Lake Washington Sightseeing Cruise. Enjoy Lake Union and Lake Washington on this 2-hour sightseeing cruise, including a live narration of the region's fascinating past. Discover how the area started a new chapter in the history of aviation; learn about the region's transformation from pristine wilderness to bio-tech pioneer. See the historic houseboats and spectacular views from the lake. Book this Tour and Save 12% Off South Lake Union - Lake Washington Sightseeing Cruise.