A French aeroplane bombed Frankfort-on-the-Main on March 17, 1917, causing only little damage.
On April 5, 1917, a German aeroplane again bombed the Kentish coast town without causing any damage.
Freiburg-im-Breisgau was once more the object of an attack by English aeroplanes, made, as announced later, in reprisal for the torpedoing of British hospital ships. Ten civilians and one soldier were killed, and twenty-seven civilians, mostly women and children, wounded. Three of the British aeroplanes were shot down. Considerable damage to public buildings was caused.
On May 5, 1917, Odessa, the Russian port on the north shore of the Black Sea, was visited for the first time by a German aeroplane.
On May 14, 1917, British naval forces detected a Zeppelin in the act of approaching the English coast. The alarm was given immediately and a squadron of British seaplanes was sent after the invader. The fire from the machine gun of one of these soon reached the big airship, and before long the latter was seen to burst into flames and disappeared.
During the night of May 23, 1917, four or five Zeppelins appeared over East Anglia and penetrated some distance inland. Bombs were dropped in a number of country districts. One man was killed, but otherwise the damage was negligible.
Two days later, May 25, 1917, early in the evening, seventeen aeroplanes appeared over Folkestone on the southeast coast of England. They dropped about fifty bombs. As a result seventy-six persons were killed and 174 injured, most of them civilians, and a large percentage of these women and children. The returning German aeroplanes were pursued by machines of the British Naval Air Service from Dunkirk and attacked. Three German machines were shot down.
Again on June 5, 1917, sixteen German aeroplanes appeared over Essex and the Medway. They succeeded in dropping a large number of bombs which caused two casualties and considerable material damage and injured twenty-nine persons before antiaircraft guns and British planes drove them off. At least four German machines were shot down.
On June 11, 1917, a British patrol boat sighted five German aeroplanes off Dover. Attacking them at once, the British craft destroyed two of the machines and captured their pilots. The remaining three German machines fled.
At noon of June 13, 1917, London was subjected to the most extensive and destructive raid in its experience. In the middle of a beautiful summer day fifteen German aeroplanes appeared over London and dispatched their death-dealing burden of explosives on England's capital; 157 men, women, and children were killed, and 432 injured. Considerable material damage was caused, although the raid lasted only fifteen minutes. All but one of the German planes escaped. The East End, London's tenement district, inhabited chiefly by the poor, was the principal sufferer.