The Amazon is the world's largest tropical rainforest. It covers an area of nearly 2.8 million square miles, which is nearly the size of the continent of Australia. The Amazon Rainforest gets its life from the majestic Amazon River, the world's second largest river, which runs directly through the heart of the region. The rainforest itself is simply the drainage basin for the river and its many tributaries. The vast forest itself consists of four layers, each featuring its own ecosystems and specially adapted plants and animals.