Germany invaded the Netherlands on May 10, 1940. Four days later, German planes bombed Rotterdam. The Germans tried to halt the raid on the city because Dutch authorities had agreed to negotiate the surrender of their country. However, a communications failure delayed the order halting the attack. The bombing destroyed much of the city center, leaving almost 80,000 people homeless. The Netherlands surrendered just a few hours later. On May 15, in retaliation for the bombing of Rotterdam, the British air force attacked German industry in the Ruhr.