Large Scale Exercise (LSE) is a triennial exercise conducted by U.S. Fleet Forces Command, U.S. Pacific Fleet, and U.S. Naval Forces Europe that is designed to refine how we synchronize maritime operations across multiple Fleets, in support of the joint force. The training is based on a progression of scenarios that will assess and refine modern warfare concepts, including Distributed Maritime Operations, Expeditionary Advanced Base Operations, and Littoral Operations in a Contested Environment. LSE 2021 is the first iteration of what will become a triennial exercise with plans for future iterations to include partners and allies from around the world.