Aerial photography has been an important business area for the legendary airline Swissair since its founding in 1931. Walter Mittelholzer (1894-1937), a trained photographer and aviation pioneer, was the driving force behind Swissair Photo AG. The collection, which is now preserved in the image archive of the ETH Library, contains around 95,000 aerial images, mostly from Switzerland, and spans from the founding of its predecessor company Ad Astra Aero AG in 1918 to 2011. About 12,500 of these images were taken by Mittelholzer himself. Breathtakingly beautiful oblique and vertical shots of mountains, landscapes, cities, and villages in Switzerland—starting around 1960 also in color—vividly illustrate the transformation from an agricultural country to a densely populated area within just a few decades.