Hula Hoop Flash Mob at Austrian Hoop Convention. Hoopers take Vienna by storm with LED hoops and hula hoops galore during the Austrian Hoop Convention. Gathering at Stephansdome, Vienna’s main monument, the light trails from LED hoopers and the spectacle of everyone spinning things up, including some familiar faces, is most captivating indeed. VThe : Stephansdome. Video by organizer Lisa Looping.