Count Ferdinand von Zeppelin was the inventor of the rigid airship, or dirigible balloon. He was born July 8, 1838, in Konstanz, Prussia, and educated at the Ludwigsburg Military Academy and the University of Tübingen. Ferdinand von Zeppelin entered the Prussian army in 1858. Zeppelin went to the United States in 1863 to work as a military observer for the Union army in the American Civil War and later explored the headwaters of the Mississippi River, making his first balloon flight while he was in Minnesota. He served in the Franco-Prussian War of 1870–71, and retired in 1891 with the rank of brigadier general. Ferdinand von Zeppelin spent nearly a decade developing the dirigible. The first of many rigid dirigibles, called zeppelins in his honor, was completed in 1900. He made the first directed flight on July 2, 1900. In 1910, a zeppelin provided the first commercial air service for passengers. By his death in 1917, he had built a zeppelin fleet, some of which were used to bomb London during World War I. However, they were too slow and explosive a target in wartime and too fragile to withstand bad weather. They were found to be vulnerable to antiaircraft fire, and about 40 were shot down over London. After the war, they were used in commercial flights until the crash of the Hindenburg in 1937. Ferdinand von Zeppelin died on March 8, 1917.