 Philadelphia hosts numerous local and collegiate rowing clubs and competitions, including the annual Dad Vail Regatta, which is the largest intercollegiate rowing event in North America with more than 100 U.S and Canadian colleges and universities participating; the annual Stotesbury Cup Regatta, which is billed as the world's oldest and largest rowing event for high school students; and the Head of the Schuylkill Regatta.The regattas are held on the Schuylkill River and organized by the Schuylkill Navy, an association of area rowing clubs that has produced numerous Olympic rowers.The Philadelphia Spinners were a professional ultimate team in Major League Ultimate (MLU) until 2016.