The columned, temple-like Palácio da Assembleia da República (Palácio de São Bento) is where Portugal’s parliament, the Assembleia da República, makes its home. It was once the enormous Benedictine Mosteiro de São Bento, and is decorated with lofty Doric columns and graceful statues of temperance, prudence, fortitude and justice.
It's closed to the public and can only be visited via themed guided tours on the last Saturday of the month (free; maximum of 50 people). You must schedule your visit in advance on the website – reachable only through the Portuguese version: Click through 'Visitas Parlamento' on the right-hand side, then 'Visitas Guidas ao Parlamento', then 'Pedido de Visita ao Sábado' and fill out the English form.