U.S. Marines set up their mortar to take communist positions under fire near Chosin Reservoir. - U.S. Marines set up their mortar to take communist positions under fire near Chosin Reservoir.

What it Takes to Move a Mountain: The Regimental Air Assault - Marines with 1st Marine Division load onto an MV-22B Osprey from Marine Medium Tiltrotor Squadron (VMM) 165, Marine Aircraft Group (MAG) 16, 3rd Marine Aircraft Wing (MAW), for a regimental air assault during exercise Steel Knight aboard Marine Corps Air Station Camp Pendleton, Calif., Dec. 10, 2019. Steel Knight is an annual exercise that integrates 3rd MAW’s combat power and capabilities with those of 1st Marine Division. This exercise provides the Marines and sailors of 3rd MAW with realistic and relevant training, which enhances their skills, tactics and combat readiness. (U.S. Marine Corps photo by Warrant Officer Justin M. Pack)

U.S. Marines with Fox Battery, 2nd Battalion, 11th Marine Regiment, 1st Marine Division, fire an M777 howitzer during Summer Fire Exercise 19 at 62 Area on Marine Corps Base Camp Pendleton, California, July 23, 2019. The Marines are conducting Summer FIREX, a live-fire regimental-level exercise, from July 22 to Aug. 1. The exercise is designed to bring the entire regiment together and maximize the training areas available on Camp Pendleton to enhance their ability to conduct real-world operations. - U.S. Marines with Fox Battery, 2nd Battalion, 11th Marine Regiment, 1st Marine Division, fire an M777 howitzer during Summer Fire Exercise 19 at 62 Area on Marine Corps Base Camp Pendleton, California, July 23, 2019. The Marines are conducting Summer FIREX, a live-fire regimental-level exercise, from July 22 to Aug. 1. The exercise is designed to bring the entire regiment together and maximize the training areas available on Camp Pendleton to enhance their ability to conduct real-world operations.

A U.S. Marine with Company I, 3rd Battalion, 7th Marine Regiment, 1st Marine Division, engages a target utilizing the M240G during a squad attack at Marine Corps Air Ground Combat Center, Twentynine Palms, Calif., July 15, 2019. The training was conducted to validate the squad leaders capabilities to lead and control their squads while integrating supporting arms in a deliberate attack. - A U.S. Marine with Company I, 3rd Battalion, 7th Marine Regiment, 1st Marine Division, engages a target utilizing the M240G during a squad attack at Marine Corps Air Ground Combat Center, Twentynine Palms, Calif., July 15, 2019. The training was conducted to validate the squad leaders capabilities to lead and control their squads while integrating supporting arms in a deliberate attack.

U.S. Marine Corps 1st Lt. Ryan McCormic, the motor transport officer with 2nd Battalion, 7th Marine Regiment, 1st Marine Division, showcases 3D printing capabilities at Marine Corps Air Ground Combat Center, Twentynine Palms, Calif., Feb. 19, 2018. - U.S. Marine Corps 1st Lt. Ryan McCormic, the motor transport officer with 2nd Battalion, 7th Marine Regiment, 1st Marine Division, showcases 3D printing capabilities at Marine Corps Air Ground Combat Center, Twentynine Palms, Calif., Feb. 19, 2018. 2nd Battalion, 7th Marine Regiment is the first infantry battalion on the west coast to implement 3D printing at their unit. (U.S. Marine Corps photo by Cpl. Joseph Prado)

The photo depicts the 1st Marine Division Headquarters Building on Marine Corps Base Camp Pendleton, California, May 17, 2018. - The photo depicts the 1st Marine Division Headquarters Building on Marine Corps Base Camp Pendleton, California, May 17, 2018. The building, commonly referred to as the white house, has been the workspace for numerous commanding generals and special staff of the 1st Marine Division. (U.S. Marine Corps photo by Cpl. Joseph Prado)

U.S. Marine Corps Cpl. Michael Captain, boxing team co-captain, 1st Marine Division. The Marines are scheduled to compete in boxing contests against the Royal Marines May 3, 2018 at the Commando Training Centre Royal Marines in Lympstone, England, and May 8, 2018 at the Royal Lancaster Hotel in London, England. - U.S. Marine Corps Cpl. Michael Captain, boxing team co-captain, 1st Marine Division. The Marines are scheduled to compete in boxing contests against the Royal Marines May 3, 2018 at the Commando Training Centre Royal Marines in Lympstone, England, and May 8, 2018 at the Royal Lancaster Hotel in London, England.

A UH-1Y Huey with Marine Light Attack Helicopter Squadron 369 prepares to land after Marines with 1st Reconnaissance Battalion, 1st Marine Division, finished a fast-rope drill at Marine Corps Base Camp Pendleton, California, Oct. 6, 2016. The fast-rope training was part of a larger event called a Marine Air-Ground Task Force integration exercise, which enabled air and ground units to come together and cooperate in various training missions prior to their deployment with the 15th Marine Expeditionary Unit. - A UH-1Y Huey with Marine Light Attack Helicopter Squadron 369 prepares to land after Marines with 1st Reconnaissance Battalion, 1st Marine Division, finished a fast-rope drill at Marine Corps Base Camp Pendleton, California, Oct. 6, 2016. The fast-rope training was part of a larger event called a Marine Air-Ground Task Force integration exercise, which enabled air and ground units to come together and cooperate in various training missions prior to their deployment with the 15th Marine Expeditionary Unit.

Lance Cpl. Skyler Schopf, team leader, 3rd Battalion, 4th Marine Regiment, fires a M136 AT4 anti-tank weapon during a live-fire training exercise as part of Tactical Small-Unit Leadership Course at Marine Corps Air Ground Combat Center, Twentynine Palms, California, July 18, 2016. The purpose of the course was to focus on the training of small-unit leadership within “Darkside.” - Lance Cpl. Skyler Schopf, team leader, 3rd Battalion, 4th Marine Regiment, fires a M136 AT4 anti-tank weapon during a live-fire training exercise as part of Tactical Small-Unit Leadership Course at Marine Corps Air Ground Combat Center, Twentynine Palms, California, July 18, 2016. The purpose of the course was to focus on the training of small-unit leadership within “Darkside.”

Maj. Misty Posey the Plans Officer with the Manpower Integration Office, Headquarters Marine Corps, educates an audience about the integration of female Marines into previously closed combat arms occupations and units at the Unit Event Center June 8, 2016. The goal of integration education training is to ensure commanders and staffs are sufficiently educated and prepared to receive Marines of either gender by October 31, 2016 (active) and January 31, 2017 (reserve). “I hope we get to the point where people look at female Marines as Marines first and as women second,” Posey said. - Maj. Misty Posey the Plans Officer with the Manpower Integration Office, Headquarters Marine Corps, educates an audience about the integration of female Marines into previously closed combat arms occupations and units at the Unit Event Center June 8, 2016. The goal of integration education training is to ensure commanders and staffs are sufficiently educated and prepared to receive Marines of either gender by October 31, 2016 (active) and January 31, 2017 (reserve). “I hope we get to the point where people look at female Marines as Marines first and as women second,” Posey said.

Marines with Company A, 1st Reconnaissance Battalion, 1st Marine Division, advance to their objective during an amphibious operations training exercise as part of an Expeditionary Operations Training Group course at Marine Corps Base Camp Pendleton, California, April 21, 2016. The Marines conducted beach surveys from designated positions in the ocean, where they observed and reported information to their headquarters team. - Marines with Company A, 1st Reconnaissance Battalion, 1st Marine Division, advance to their objective during an amphibious operations training exercise as part of an Expeditionary Operations Training Group course at Marine Corps Base Camp Pendleton, California, April 21, 2016. The Marines conducted beach surveys from designated positions in the ocean, where they observed and reported information to their headquarters team.

A Marine with Battery Q, 5th Battalion, 11th Marine Regiment, I Marine Expeditionary Force, guides a High Mobility Artillery Rocket System launcher during Spring Fire Exercise at Marine Corps Base Camp Pendleton March 31, 2016. The regiment, comprised of four artillery battalions and a headquarters battalion, put their skills to the test during a large-scale, combined-arms training evolution in preparation for future deployments and operations. - A Marine with Battery Q, 5th Battalion, 11th Marine Regiment, I Marine Expeditionary Force, guides a High Mobility Artillery Rocket System launcher during Spring Fire Exercise at Marine Corps Base Camp Pendleton March 31, 2016. The regiment, comprised of four artillery battalions and a headquarters battalion, put their skills to the test during a large-scale, combined-arms training evolution in preparation for future deployments and operations.

Cpl. Richard Nedlic (Right), Light Armored Vehicle crewman and Cpl. Nicholas Guiles, rifleman, both with 1st Light Armored Reconnaissance Battalion and students in the Urban Leaders Course, fire their weapons from the supine position during a combat marksmanship program range at Marine Corps Base Camp Pendleton, California, March 31, 2016. This firing drill is meant to train Marines to safely and accurately return fire if they fall backward while moving or are knocked down. - Cpl. Richard Nedlic (Right), Light Armored Vehicle crewman and Cpl. Nicholas Guiles, rifleman, both with 1st Light Armored Reconnaissance Battalion and students in the Urban Leaders Course, fire their weapons from the supine position during a combat marksmanship program range at Marine Corps Base Camp Pendleton, California, March 31, 2016. This firing drill is meant to train Marines to safely and accurately return fire if they fall backward while moving or are knocked down.