Question: Palácio de Ferro is located in the capital city with a population over what figure?
Sentence (from "Luanda"): It is also the capital city of Luanda Province, and the world's fourth most populous Portuguese-speaking city, behind only São Paulo, Rio de Janeiro, and Salvador, Bahia all in Brazil, and the most populous Portuguese-speaking capital city in the world, ahead of Brasília, Maputo and Lisbon.
Relevant evidence: No