Condensation from liquid oxygen tanks hits the air and freezes inside in a hardened aircraft shelter at Keflavik International Airport, Iceland, April 2, 2016. Electro-environmental technicians assigned to the 104th Maintenance Group, Barnes Air National Guard Base, Mass., transfer the oxygen into portable units that can replenish oxygen supplies in aircraft. Four U.S. Air Force F-15C Eagle fighter aircraft, assigned to the 104th Fighter Wing, deployed to Keflavik, Iceland, to support Icelandic Air Surveillance operations throughout April. (U.S. Air Force photo by Master Sgt. Kevin Nichols/Released)