Red tape marked the explosive charge U.S. soldiers set on the plywood to breach the door to a brick house. Ready to ignite it, they hunkered down along the wall their weapons at the ready. Repeated shouts of “fire in the hole” rang out, and after a loud boom, the six-man unit dashed into the building. Nearby, British soldiers carefully cleared a brick house room by room as Polish helicopters whirred above.

The furious activity at military base near Wedrzyn in western Poland was part of one of the largest NATO exercises since the end of the Cold War. Some 30,000 troops, and numerous vehicles, aircraft and ships from more than 20 countries were involved in the show of force aimed at reassuring the U.S. allies unnerved by Russia’s actions in nearby Ukraine. READ MORE