|Animation of a flight to the planet Venus, descending through its atmosphere and flying over the surface. Venus is the second planet from the Sun, and is similar in size to Earth. It is covered in a thick, dense atmosphere of mainly carbon dioxide, with clouds of sulfuric acid. The atmosphere has 93 times the mass of Earth's, and the atmospheric pressure on the surface is 93 times greater, similar to the pressure 900 metres below the sea. The huge amount of carbon dioxide produces a strong greenhouse effect, and the surface is has a temperature of some 476 degrees Celsius, making Venus the hottest planet in the Solar System. The surface is marked by volcanoes and lava flows, and volcanic activity is ongoing. At the end of the clip, the remains of the Venera 9 space probe are seen. This Soviet spacecraft became the first to return images from the surface of another planet when it landed in 1975.