Carl Benz filed a patent for a vehicle with a gas engine on 29 January 1886. It was granted on 2 November 1886. On 3 July 1886 he made the first public test drive in Mannheim. In 2011 UNESCO added the patent to its Memory of the World register. Benz’s three-wheeler is described as the world’s first practical motor car with a combustion engine. Steam vehicles had been in use long before. In August 1888 his wife Bertha drove it from Mannheim to Pforzheim with their two teenage sons, without her husband’s knowledge. A pharmacy in Wiesloch, where she bought fuel, is considered the world’s first filling station. Her experiences on the drive fed into later cars, among them a low gear for steep hills and leather linings for the brakes. In 1925 Benz’s memoirs appeared under the title Lebensfahrt eines deutschen Erfinders, The Life Journey of a German Inventor. They were written by his son-in-law and authorized by Benz.