Palau Sant Jordi (Sant Jordi Sports Palace) by the Japanese architect Arata Isozaki with capacity for 17,000 spectators is the main attraction at Barcelona Olympic ring. Built from August 1985 to September 1990, it can hold a wide variety of sports events or stage big concerts. The concave metallic structure on top is covered with ceramic tiles and zinc sheets. The enormous square full of columns and fountains together with the flying saucer appearance of the pavilion might as well be a magnificent scenario for a sci fi movie (it reminds me of Star Wars). I caught two people walking on the left for a better appreciation of its magnitude.
See Palau Sant Jordi Picture on a Google Earth Map.