A rainforest is a forest characterized by high rainfall, with annual rainfall in the case of tropical rainforests between 250 and 450 centimetres (98 and 177 in), and definitions varying by region for temperate rainforests. The monsoon trough, alternatively known as the intertropical convergence zone, plays a significant role in creating the climatic conditions necessary for the Earth's tropical rainforests. Around 40% to 75% of all biotic species are indigenous to the rainforests. There are an estimated 10 million different species living in the world’s rainforests. These species include insects, reptiles, amphibians, mammals, and birds. Many of these species are still undiscovered. Tropical rainforests are found near the Earth’s equator. The largest tropical rainforest in the world is the Amazon rainforest. The Amazon rainforest covers more than 2 million square miles (5.4 million square kilometers). The Amazon rainforest is found in South America. Other tropical rainforests are found in Central America, Africa, and Southeast Asia. Tropical rainforests are home to many plants and animals. More than half of the world’s plants and animals live in tropical rainforests. The rainforest is a very important part of the Earth’s ecosystem.The rainforest is being destroyed at a rate of 6000 acres every hour. That’s equivalent to 10 square miles (27 square kilometers) every day. The main reason rainforests are being destroyed is for the lumber and agricultural industries. Every year, millions of acres of rainforest are cleared for lumber and to make room for farms and pasture.