A Sky-High View from Outside the John Hancock Center

A worker preparing to replace the west antenna atop the John Hancock Center strapped a video camera to his helmet and recently posted to YouTube this breathtaking 12-minute recording of what he and his co-workers see and do while on the job.

The iconic 100-story Chicago building stands 1,506 feet tall at the tip of its eastern antenna. About 46,000 tons of steel went into its construction, which began in 1965 and finished in 1969. In 2012, a company paid $70 million for ownership of the antennas on top of the skyscraper.