For the millions of tourists who visit Amsterdam each year, solar panels will soon be a common sight on the Dutch city's famous canalside houses, much to the dismay of local heritage groups. "Of course, sustainability is important, but in our opinion, these solar panels are really ugly," says Karel Loeff, president of one such group seeking to preserve the UNESCO World Heritage Site. Solar panels are already allowed on the roofs of protected monuments as long as they are not visible from the street, a condition the local council now wants to relax. IMAGES AND SOUNDBITES