The Buda Castle Hill in Budapest with its natural and artificial relics is an invaluable part of World’s Heritage. Cellars and caves, castle-walls and retaining walls, dwelling houses and palaces are the components which are in a tight relationship with each other and the urban environment too. The geological milieu is formed of marl covered by limestone and topsoil. The task of geophysics - on the basis of long-term city-planning - was to investigate the geological structure (especially the relief of the rock bed) and to detect archeological objects in three different areas.