The two longest rivers in the world are the Nile River in Africa and the Amazon River in South America. The Nile measures about 6,650 kilometers (4,130 miles) and flows through several countries, including Egypt and Sudan, leading to the Mediterranean Sea. The Amazon, which spans approximately 6,400 kilometers (4,000 miles), winds through countries like Brazil and Peru, ultimately emptying into the Atlantic Ocean. Both rivers are crucial for their respective ecosystems and human populations, providing water, transport, and biodiversity.