The long queues in front of Angola's pavilion at the Venice Biennale bear witness to the extraordinary success that Africa has just had at the "Olympics of the art world". Ever since it was announced that, out of 88 contenders, Angola had won the Golden Lion award for the best national participation, art lovers and journalists from all over the world have been flocking across the Accademia bridge - from the distant main exhibition areas, the Giardini and the Arsenale - to try to see the show.