 The entire Linz project was treated as a state secret on Hitler's order.The collection for the planned museum in Linz was accumulated through several methods.Hitler himself sent Heinrich Heim, one of Martin Bormann's adjutants who had expertise in paintings and graphics, on trips to Italy and France to buy artworks, which Hitler paid for with his own money, which came from sales of "Mein Kampf", real estate speculation on land in the area of the "Berghof", Hitler's mountain retreat on the Obersalzberg, and royalties from Hitler's image used on postage stamps.