Workers Scale Top of St. Louis Gateway Arch

— -- What does it take to scale the nation’s tallest monument, at 630 feet in the air?

The National Park Service has given the world a glimpse in newly-released video filmed with helmet cams worn by workers atop St. Louis' famed Gateway Arch.

The workers were hired by the Park Service to inspect the arch for possible corrosion. They can be seen in the video rope-climbing to reach the arch’s peak, while wearing harnesses and helmets for safety.

Once atop, the workers’ helmet cams give a jaw-dropping view of the landscape 630 feet below.