Early in the morning, the pioneer car traveled to the Oracle area of Arizona to visit the largest artificial ecological circulatory system, Biosphere 2, established in the 1990s. Listening to the explanation, the simulation of the Earth's biological system in the circle, from deserts, marshes, prairie, tropical rainforests to the ocean, a total of five biotas and more than 3,800 species of plants and animals, the whole project cost more than 100 million dollars, but the experiment of "Biosphere 2" still failed. It also proves that under the current scientific and technological conditions, the Earth is still the only living system that humans can rely on and trust. So, everyone must protect the Earth.