The U.S. Air Force Academy (USAFA) held its large-scale annual "CULEX," or culminating training exercise, on Thursday, giving cadets a realistic look at a combat scenario. The 24-hour-a-day exercise places nearly 4,000 cadets in a mock war setting, where upperclassmen lead complex missions and younger students follow orders. This year, it runs April 15 through April 18. The Air Force Academy is 18,500 acres, nestled in the foothills of the Rocky Mountains, but on Thursday, the culminating exercise scenario transformed USAFA into Hokkaido, a Japanese island under attack by enemy forces. "We've pretty much taken over the entirety of USAFA, to allow all 4,000 of our cadets to have space to operate throughout the exercise," said CULEX director Col. Jennifer Hall. 'FLY' YOUR OWN AIRCRAFT IN US AIR FORCE ACADEMY HOTEL'S FIRST-EVER FLIGHT SIMULATORS In the war scenario, Japan has asked the U.S. to come in as a defensive force. "In this scenario, we have four established airfields," Hall said.…