Massive, Army-led NATO exercise Defender Europe kicks off March 15 M1 Abrams tanks stand ready to be loaded onto American Roll-on Roll-Off Carrier s Endurance in Savannah, Ga., in February 2020 for Defender Europe 20. (Pfc. Carlos Cuebas Fantauzzi/Army) One of the largest U.S.-Army led military exercises in decades has kicked off and will run until June, with 28,000 total troops from 27 nations taking part. Defender Europe 2021 will include “nearly simultaneous operations across more than 30 training areas” in a dozen countries. The exercise is the deployment of a division-size force from the United States to Europe, pulling equipment from Army prepositioned stocks, then moving personnel and equipment across the theater to multiple training areas.