There is a backstory to this map. Between 27 November and 5 December of 2012, several hundred clerks at the Ports of Los Angeles and Long Beach went on strike. Port clerks are responsible for managing the transition of cargo between logistics networks and are essential to the operation of the ports. They also belonged to the International Longshore and Warehouse Union, so the rest of the 10,000 workers at the ports refused to cross the picket line in solidarity with the strikers, effectively shutting down the ports.