At the start of the war, the German Empire had cruisers scattered across the globe, some of which were subsequently used to attack Allied merchant shipping. The British Royal Navy systematically hunted them down, though not without some embarrassment from its inability to protect Allied shipping. However, the bulk of the German East-Asia squadron did not have orders to raid shipping and was instead underway to Germany when it encountered elements of the British fleet. Soon after the outbreak of hostilities, Britain initiated a naval blockade of Germany. The strategy proved effective, cutting off vital military and civilian supplies. The 1916 Battle of Jutland developed into the largest naval battle of the war, the only full-scale clash of battleships during the war. The Kaiserliche Marine's High Seas Fleet squared off against the Royal Navy's Grand Fleet. The engagement was a stand-off as the Germans, outmanoeuvred by the larger British fleet, managed to escape and inflict more damage to the British fleet than they received.
Strategically, however, the British asserted their control of the sea, and the bulk of the German surface fleet remained confined to port for the rest of the war. German U-boats attempted to cut the supply lines between North America and Britain. The nature of submarine warfare meant that attacks often came without warning, giving the crews of the merchant ships little hope of survival. The U-boat threat lessened in 1917, when merchant ships entered convoys escorted by destroyers. With the aid of numerous black and white and colour photographs, many previously unpublished, the History of World War I series recreates the battles and campaigns that raged across the surface of the globe, on land, at sea and in the air.