The land war in Europe became a destructive machine, consuming supplies, equipment, and soldiers at massive rates. Resupply ships from the home front and allies streamed across the Atlantic, braving submarine attacks, underwater mines, and aerial bombardment. Battleships clashed with each other from the Indian Ocean to the North Sea, competing for control of colonial territory and home ports. New technologies were invented and refined, such as submarine warfare, camouflaged hulls, and massive water-borne aircraft carriers. And countless thousands of sailors, soldiers, passengers, and crew members were sent to the bottom of the sea. I've gathered photographs of the Great War from dozens of collections, some digitized for the first time, to try to tell the story of the conflict, those caught up in it, and how much it affected the world. This entry is part 7 of a 10-part series on World War I.