In 1971 the Olympic Committee appointed Holtmann as general contractor to build the entire facilities for the sailing competition in Kiel at the Olympic Games.
After five months of work the complete Olympic Village with an indoor area of over 3.600 m² was completed and equipped with all heating, ventilation and lighting systems.
In 1973 Holtmann developed a new type of module made entirely of wood. It was introduced nationwide and protected under the name of GEO-BAU.
This construction method proved its usefulness especially for temporary buildings and was employed for many years in schools, kindergartens, youth hostels and elevations of buildings.

1950s | 1960s | 1970s | 1980s | 1990s | 2000 - Expo year | 2000s | today