2500 NATO troops have set up camp at RAF ST Mawgan in Cornwall in what's being described as the largest deployment to the South West since World War II.
It's all part of an enormous two-week military training exercise involving hundreds of foreign troops.
The base is celebrating its 70th anniversary this year - and what a way to show to the world it is still as useful as ever.
The headquarters of this giant operation is a tented village which has sprung up on the base for the largest land deployment in Europe.
Our reporter Francesca Carpenter went inside the base to see what was happening