Online shopping seems like a straightforward process: hunt down the perfect item, trudge through the checkout pipeline and await a package's inevitable arrival. The trip between a warehouse and your doorstep, however, involves meticulous organization on a massive scale. In order to pull off such a feat, United Parcel Service (UPS) relies on Worldport in Louisville, Ky.: a 5.2 million-square-foot processing facility that's capable of sorting up to 416,000 packages an hour. Within Worldport, 70 aircraft docks and 155 miles of conveyor belts await the arrival of packages from over 220 countries and territories. So, what happens when UPS gets ahold of those parcels destined for air delivery? The folks clad in brown took us inside their largest sorting hub to find out.