U.S. Marines with SPMAGTF Crisis Response - Africa load bags of concrete, that will be used by local and international health organizations to build Ebola Treatment Units, into an MV-22B Osprey during Operation United Assistance in Monrovia, Liberia, Nov. 21, 2014. United Assistance is a Department of Defense operation to provide command and control, logistics, training, and engineering support to U.S. Agency for International Development- led efforts to contain the Ebola virus outbreak in West African nations. (U.S. Marine Corps photo by Lance Cpl. Andre Dakis/ SPMAGTF-CR-AF Combat Camera/Released)