Air traffic controllers at Atlanta Hartsfield-Jackson International Airport are in charge of 190,431 takeoffs and landings at the world's busiest airport (in a normal year). But the job isn't easy. Not only are lives on the line, but any mistake at Atlanta could cause a ripple effect of delays across the country and the world. Pre-pandemic, Business Insider went up inside America's tallest air traffic control tower to learn what it takes to be one of the 58 air traffic controllers there.