Window washing at The Cortland is a sight to see… 
These guys have all the gear - and skill - of a mountain climber.
I assume this is how the windows on tall buildings get cleaned if there is no crane/lift machine mounted on top of the building.
The windows above the ground floor are not multi-pane windows: better views out, and easier to clean as well. Look at all that gear. I have 47 previous posts on this topic. Click on my infoshare tag above to see all my photos, comments & links.