Fans of the Brazilian band Blitz attend a concert at the Rock in Rio Festival in the Olympic Park, Rio de Janeiro, Brazil, on September 16, 2017. Running for seven days in all -- Friday through Sunday and then September 21 to 24 -- Rock in Rio is being welcomed by the city as a chance to put the huge facilities built for the 2016 Olympic Games back in use. Rock in Rio is one of the world's biggest music events and this year's edition is three times bigger than in previous years. / AFP PHOTO / Mauro PIMENTEL