There is a long tradition of cartography and the art of building relief maps in Switzerland. Xaver Imfeld (1853–1909) and Eduard Imhof (1895–1986), two of the most important figures in this field, have both left significant works in this discipline. Imfeld was employed at the Eidgenössisches Topographisches Bureau and became a pioneer in the planning of mountain railways for tourists. Imhof was a professor for many years, as well as founder of the Institute of Cartography at the Swiss Federal Institute of Technology Zurich (ETH); he remains an influential figure in Swiss mapping history. Imhof taught himself how to model plaster relief maps. His two most important mountain models, Bietschhorn and Windgälle, were created for the Swiss National Exhibition in 1939.