Where are all portuguese people on Sundays???

Walking around this city, there are always people everywhere; the small narrow streets in Cic's "hood", in the park, in the pastelarias, at the uni, at the footbalcourt, at Avenida de Liberdade, the metro of course, in Oriente, Alfama, Baixa and Chaido, you name it... BUT on sunday mornings they all disappear *poof*. No one - no where... Well as I had a relaxing weekend this weekend I got the chance to get up normal (swedish" time, i.e around noon and actually walk outdoors (since I'm in Portugal and it is still nice weather), I noticed that there's no life in town. I recalled the very first day here, when João had to pick me up "early" on a Sunday and was surprised how empty the streets were. And believe me, they are.... =))