The state's largest cities are Rio de Janeiro, Nova Iguaçu, Niterói, Duque de Caxias, São Gonçalo, São João de Meriti, Campos dos Goytacazes, Petrópolis and Volta Redonda. Its main rivers are the Guandu River, the Piraí, the Paraíba do Sul, the Macaé and the Muriaé. Its climate is tropical.