Soldiers from across Europe suited up in heavy diving equipment inside a cavernous flooded stone quarry deep beneath the Hungarian capital. Once their air tanks, flippers and waterproof diving suits were secured, they slipped beneath the cold water and, flashlights in hand, disappeared into the darkness. The military divers from Belgium, Germany, Hungary and Lithuania were participating in an international training exercise in Budapest to prepare them for a variety of scenarios: recovery operations after a boat accident, rescues during a catastrophic flood, or the removal of unexploded underwater ordnance following an armed conflict.