Forces News has been granted exclusive access to the NATO team helping to plan a major US-led exercise.
Exercise Defender-Europe 20 is the largest deployment of American troops to an exercise in Europe for 25 years.
More than 20,000 American troops will join personnel from NATO nations and partners for the exercise that is being planned, in part, at the Allied Rapid Reaction Corps (ARRC) Headquarters in Gloucestershire.
"It's the largest exercise of its nature," ARRC Commander, Lieutenant General Sir Edward Smyth-Osbourne told Forces News in his first broadcast interview since assuming the post.
"It focuses, unequivocally, on multi-domain operations.
"It not only looks at the traditional spheres - of the sea, the land and the air - but it also incorporates cyber and space."
The exercise is designed to test the ability of partner nations to readily deploy forces to defend against potential aggression and deter adversaries.
Tens of thousands of troops will transit through Belgium, Germany, Poland and up to the Baltic States for the exercise.
Major General Maciej Jablonski, Commander 12th Polish Mechanised Division, told Forces News the exercise is "extremely important" for Polish defence.
Meanwhile, Defender-Europe 20 is also proof that the US is committed to NATO, according to one American General.
Under President Donald Trump, the US has threatened to quit the alliance.
Mr Trump has regularly urged other NATO nations to increase their spending, accusing them of relying on the US.
But Brigadier General Matthew Van Wagenen, ARRC Deputy Chief of Staff Operations, told Forces News: "I think actions speak.
"Over 22,000 soldiers will return to Europe with 17,000 pieces of equipment and be here for a duration of up to six months.
"If that doesn't reassure our commitment to NATO, I don't know what does."
Cover Image: Vehicles and equipment are already being moved for the exercise (Picture: US Department of Defense).