BOSTON (May 18, 2018) Fireman Gabriel Lupo, assigned to USS Constitution, climbs the ship’s mizzenmast during ‘Old Ironsides' underway commemorating the Vietnam War. In coordination with the United States of America Vietnam War Commemoration, the crew of USS Constitution hosted Vietnam veterans onboard as a thank you for their years of service and sacrifice for their country. (MC3 Casey Scoular/Navy)
Air Force Lt. Col. Chuck Anthony wears a gas mask as he stands next to a wall of lava entering the ocean near Pahoa, Hawaii. White plumes of acid and extremely fine shards of glass billowed into the sky over Hawaii as molten rock from Kilauea volcano poured into the ocean, creating yet another hazard from an eruption that began more than two weeks ago: A toxic steam cloud. (AP Photo/Jae C. Hong, file)
Members of the freshman class sing the Navy Blue and Gold at the end of the annual Herndon Monument Climb May 21, 2018 at the U.S. Naval Academy in Annapolis, Maryland. The first year midshipmen formed and climbed a human pyramid around the 21-foot-tall Herndon Monument, which was covered with about 50 pounds of vegetable shortening, to replace the plebe hat, also known as a "dixie cup", on the top of the monument with an upperclassman's hat. (Photo by Alex Wong/Getty Images)
Marine Sgt. Nicholas R. Wetzel, a combat instructor assigned to Kilo Company, Marine Combat Training Battalion, School of Infantry-East, throws a ground burst projectile simulator C1A1 during a live fire and maneuver exercise at Camp Lejeune, North Carolina. (Sgt. James R. Skelton/Marines)
A Marines M1A1 Abrams tank is shrouded in sand during a low-light live-fire exercise as part of Exercise Arrow 18 in Pohjankangas Training Area near Kankaanpaa, Finland, May 16, 2018. Marines with Bravo Company, 4th Tanks Battalion, participated in this live-fire exercise with the Finnish Leopard tanks. Exercise Arrow is an annual Finnish multi-national exercise with the purpose of training with mechanized infantry, artillery, and mortar field training skills in a live-fire exercise. This is the first year the Marine Corps is participating in this exercise and the first time the M1A1 Abrams tanks have been in Finland. (Sgt. Averi Coppa/Marines)
U.S. Air Force Maj. Paul "Loco" Lopez, F-22 Raptor Demonstration Team commander and pilot, performs during AirPower Over Hampton Roads JBLE Air and Space Expo at Joint Base Langley-Eustis, Virginia, May 18, 2018. The Raptor performs both air-to-air and air-to-ground missions allowing full realization of operational concepts vital to the 21st century Air Force. (Staff Sgt. Areca T. Bell/Air Force)
U.S. Marines with 2nd Light Armored Reconnaissance Battalion, 2nd Marine Division conduct a float test in Light Armored Vehicles during water obstacle negotiation training at Camp Lejeune, N.C., May 17, 2018. The event enhanced the Marines' abilities to maneuver through aquatic terrain in LAVs in preparation for potential real-world combat scenarios. (Pfc. Tyler M. Solak/Marines)
Approximately 18,000 Army paratroopers assigned to the 82nd Airborne Division participate in the Division Run during All American Week 2018 on Fort Bragg, North Carolina. (Pfc. Alleea Oliver/Army)
U.S. Air Force Lt. Col. Frederick M. Wilmer III, a KC-10 Extender pilot with the 76th Air Refueling Squadron, 514th Air Mobility Wing, has apple cider poured on him by his daughter, Samantha, after completing his final flight at Joint Base McGuire-Dix-Lakehurst, N.J., May 18, 2018. The final flight, or fini-flight, is a tradition among pilots and air crew to celebrate one’s last flight with their unit or on a certain airframe. The 514th is an Air Force Reserve Command unit. (Master Sgt. Mark C. Olsen/Air Force)
Visitors and period re-enactors gather beside the Memphis Belle, a Boeing B-17 "Flying Fortress," on its first day of public exhibition at the National Museum of the U.S. Air Force, Thursday, May 17, 2018, in Dayton, Ohio. The B-17 "Flying Fortress" will anchor an extensive exhibit in the museum's World War II gallery, paying tribute to the thousands of men who served on B-17s on daylight bombing missions over Nazi-occupied Europe. The plane was celebrated for being the first B-17 to survive 25 missions and return to the U.S. (AP Photo/John Minchillo)
A U.S. Air Force U-2 spy plane prepares to land as South Korea and the United States conduct the Max Thunder joint military exercise at the Osan U.S. Air Base in Pyeongtaek, South Korea, Wednesday, May 16, 2018. North Korea on Wednesday canceled a high-level meeting with South Korea and threatened to scrap a historic summit next month between President Donald Trump and North Korean leader Kim Jong Un over military exercises between Seoul and Washington that Pyongyang has long claimed are invasion rehearsals. (Kwon Joon-woo/Yonhap via AP)
Plebes battle it out in a pugil stick match during the class of 2019 Sea Trials event at the Naval Academy in Annapolis, Maryland. (MC3 Kaitlin Rowell/Navy)