The British expected a second Trafalgar, but within days German submarines turned the North Sea into a no-go area for Britain's great battleships. The British responded with a blockade of Europe to starve the enemy out. Germany launched submarine attacks against civilian ships, including the Lusitania with 1,200 lives lost. American acted as arsenal and banker to the warring nations, but, though targeted by spies and saboteurs, was deeply reluctant to join in. Then top secret British code-breakers deciphered the Zimmermann Telegram which revealed that Germany was encouraging Mexico to attack America. Now America joined the First World War.