The capital of Formosa Province is a good starting point for excursions to the northern Chaco. Interesting buildings in the city include the Casa de Gobierno, which has been declared a national monument. Apart from Formosa’s annual week-long Fiesta del Río (a nocturnal religious procession), one of the main regional attractions is the massive Río Pilcomayo National Park, an area of swamps, marshland and savannah on the Paraguayan border, whose Laguna Blanca is an ideal spot for birdwatching.