The Hamza River is a recent discovery. Under the ground in the Amazon area is a huge slowly moving waterway. This slowly flowing aquifer in Brazil is about 6,000 kilometres (3,700 mi) long. It is nearly 4,000 metres (13,000 ft) below ground level. Its discovery was announced in 2011. The Hamza "river" and the Amazon River are a twin-river system flowing at different levels of the Earth's crust.