Up to 700 soldiers a day will be trained on the world's biggest battlefield simulator in Wiltshire.
The £250m gadget can recreate terrains ranging from harsh desert to lush countryside.
Once inside the simulator, soldiers are pitted against "virtual enemies" of varying abilities in one huge battle in a simulator hall the size of three football pitches.
Armed Forces minister Adam Ingram unveiled the Combined Arms Tactical Trainer (CATT) system on Wednesday.
He said: "This simulator provides an unprecedented level of activity - soldiers say the only thing missing is the smell of cordite.
"It's a case of Disney World - eat your heart out. But the serious side is that it prepares our people for the realities of combat.
"The army can train under any conditions almost anywhere in the world at the flick of a switch - without environmental impact or the cost of moving men and equipment over long distances."
The units are housed inside massive warehouses at the Land Warfare Centre in Warminster and at a British Army base in Sennelager, Germany.
Tank commander Corporal Barry Hope, of the 2nd Royal Green Jackets, based at Warminster, said: "You still get the adrenaline rush, because you still don't want to be killed do you?
"The best thing is that you stay warm and dry, unlike the real thing."