Alongside his wine and restaurant activities, Richard Unger developed his property business up to the start of World War I. After a short period of stagnation during the War, he sold products of his own manufacture under the brand name Kempinski. The business in Berlin flourished so that in 1918, a Kempinski hotel dependency was established at 27 Kurfürstendamm, where the Kempinski Hotel Bristol now stands. Ten years later, M. Kempinski & Co. took over the "Haus Vaterland" on the Potsdamer Platz, where the firm exploited a concept that was unique in Berlin for a long time and is still known as "event gastronomy" ("Erlebnisgastronomie").