Lisbon's (and Portugal's) largest indoor live music venue is also its most iconic. Designed by Regino Cruz, one of the country's most influential architects, and built for the Expo 98 World Exposition, the outer shell of this extraordinary and contemporary concert hall resembles a giant horseshoe crab in keeping with the oceans theme of the exposition. The venue has a capacity for over 4000 spectators and is well and truly placed on the international concert circuit: Prince, Madonna, Michael Bublé, Rihanna, Alicia Keys and a host of other world class acts have all played here. Furthermore, the arena is easily reached and situated within walking distance of several excellent hotels, a huge shopping mall and other visitor attractions.