All existing facilities, in the capital or elsewhere in the country, either had limited seating capacity - say up to 4,000 seated - or could only be adapted to unconventional events, such as high-level indoor sports tournaments, with great difficulty.
In addition, most venues lacked the kind of technological features required by modern TV coverage or by a major music or theatre production.
There was definitely a gap for a venue of a capacity of over 4,000 spectators, standing between venues such as Lisbon's Coliseu or a number of arenas built for other purposes that could be adapted for the effect, and large-size open-air sports stadiums.
Owing to that fact, the country was being bypassed by the organisers of indoor sports tournaments and events, and it became a problem to organise major concerts during the cold and rainy season.