evidence: South of Porto and north of Lisbon is a region of Portugal known as central Portugal. It runs east to west. Conímbriga, one of the largest Roman settlements ever discovered in Portugal, is located close to Coimbra, one of the biggest cities in the area. Aveiro, Caldas de Rainha, Leiria, and Castelo Branco are additional cities and towns in the Central Region. [...] The region around Lisbon and the Tagus Valley is the second most populous in Portugal. Within this region of the nation, there are almost 3 million residents. This region is home to Setbal, Sintra, and Cascais, among other notable cities. [...] Lisbon is perched atop seven hills, and the Tagus River dominates this region. The area is mountainous, with Sintra being another hill-dominated city. This area of Portugal is the smallest, excluding the two autonomous archipelagos.