This content was created in partnership with Aerial Cities, a new show on Smithsonian Channel that explores America's most prominent cities from breathtaking heights. Watch the series Sundays at 8/7c.
Factory workers are being replaced by computers. Taxi drivers are being replaced by autonomous vehicles. So why is the window washing industry still going strong? You might think that building a robot to clean a skyscraper would be first on the list — wouldn't it save human lives? — but in reality, getting a robot to do a window-washer's job is nothing close to easy.