The Mohawk tribe (part of the Iroquois Confederacy). Known historically as "Skywalkers," Mohawk men were famously hired for high-steel construction in the late 1800s and helped build iconic NYC landmarks like the Empire State Building and the World Trade Center.
However, it wasn't that they were not scared, but were very disciplined and respectful of the height. They trained specifically to not fall. Which would not help me.