OKINAWA, Japan (June 6, 2021) Seabees with Naval Mobile Construction Battalion (NMCB) 4, work together with Marines from 9th Engineering Support Battalion (ESB), to construct a cement bunker a cement bunker on W-174 Joint Okinawa Training Range Complex, an uninhabited island off the coast of Okinawa, Japan, during joint exercise Poseidon's Watchtower. Poseidon's Watchtower is a multi-domain exercise designed to simulate the establishment of Expeditionary Advanced Base operations through joint service integration. (U.S. Navy photo by Mass Communication Specialist 2nd Class Evan Parker)