Rio Carnival: Rio de Janeiro, Brazil Occurs from March 4th to 8th. The Biggest Party on Earth? Quite possibly. More than 2 million people hit the streets every day with stunning displays, raunchy dancing and samba beats the main theme. For backpackers in South America, the Rio Festival is an almost rites of passage and many even plan their trips around it. Be sure to sort accommodation out in advance if you’re planning on coming to Rio during the Carnival.