Hilversum is located on the sandy, hilly parts of the Gooi, and has four hills: de closest to the centre of town in the Boomberg. then the Trompenberg (now a luxury residential area where a.o. the Brenninkmeijer family lives, of C&A-fame, and to the south the Hoorneboeg (25m) and two kms easterly of that the Zwaluwenberg, where since 1950 the headquarters of the inspector-general of the armies is located. These hulls date from the period of the Ice-age, when gletschers pushed walls of earth before them. Hilversum was the farthest southern edge the gletschers reached.