Opening of Ecolonia Alphen aan den Rijn. There were three architects Queen Beatrix word might stand in Ecolonia, the first sample area that was at the forefront of sustainable building and living in the Netherlands. We had the theme "healthy and safe", which the queen wanted to be. Extensively informed Along with a resident of the homes we gave explanation. Dust-poor detailing, low temperature heating, solar energy, conservatories, central vacuum system, cleanable ventilation, low-solvent paints, etc., etc. The photo was taken by Kees Duijvestein who later became professor Sustainable Building in Delft