While much of the port activity in Seattle has shifted away from the downtown waterfront area and now takes place just south of the waterfront, the Port of Seattle main offices remain at Pier 66, which is reasonably close to Belltown and Pike Place Market.
The structure is a combination of several different things.
However, one of the lesser known but very useful (especially during sunset) is the observation deck on the roof of the building.
This rooftop observation deck comes equipped with a number of tables for those who would like to relax outside and have a bit to eat here from one of the restaurants down below, benches including a few that are raised slightly, and binoculars that are free to use.
This may be accessed from the elevators and staircases from the waterfront sidewalk, or from the overhead bridge that passes over Alaskan Way and connects Pier 66 to downtown Seattle.
The observation deck may be closed due to cruise ships occupying the pier, or various other Port of Seattle activities.
From below on the waterfront sidewalk there is no sign at all that this observation deck exists, and the only way to know that it exists at all is to already know that it is there.