Rio Iguaçu (Portuguese spelling) originates in Serra do Mar (Mountain Range of the Sea) in the Brazilian Highlands. It flows about 800 miles before reaching Iguaçu Falls. This gorge is nearly two miles long. The river covers an impressive 19 square miles within the Brazilian and Argentine parks. There are four hydroelectric plants upstream from Iguaçu Falls. They harness the river’s power while regulating water levels to optimize the waterfalls.