Built in 2000 by Skillful Means,Hidden Villa's Wolken Center was designed by Cartmell/Tam Architects of Palo Alto. It serves as an education center for the organic farm and an example of green building. The building features two feet thick rice straw bale walls, a trombe wall, concrete floors that act as a thermal mass, clearstory skylights, photovoltaic cells for electricity, and large overhangs to shield from summer sun!