Grocery delivery service Ocado, located in Andover in the United Kingdom, uses a fleet of robots to gather groceries at this high-tech warehouse. Organized on a grid above the bins, the robots move as neatly as worker bees at a speed of 8.9 miles per hour. The mesmerizing dance is coordinated by an air traffic control system using 4G, which keeps the 1,100 little guys from colliding. They handle about 64,000 orders per week. When an order comes in, the robots take the requested item from the bins to a pick station, where a human worker or more robots organize them into packages for delivery. The robots run on on-board batteries and return to a charging station when they need a top-up after a long day of retrieving packaged food. Ocado also employs about 800 people in the Andover fulfillment center.