Rio de Janeiro (AFP) - Dozens of demonstrators gathered at Rio de Janeiro's heavily polluted Guanabara Bay, demanding that officials clean it up before it is used as a 2016 Olympic sailing venue. Amid whistles of disapproval and shouts of "shame!" demonstrators held a beachside protest, their boats symbolically kept on the shore as they waved their oars in the air. They launched their protest at noon to coincide with low tide, when the dirtiness of the water is most evident. "Brazilian authorities promised a series of improvements to the bay but just a little more than a year ahead...