The next planet out from the Sun is Venus. This is the brightest object in the sky apart from the Sun and Moon. Although Venus appears beautiful when seen in the sky, it is a very hostile planet. It is covered in clouds of poisonous gases which reflect sunlight very well. The surface is extremely hot and the clouds cannot be seen through them. Recent unmanned space missions to the planet have used special instruments to map its surface. Venus has many large flat plains together with craters, valleys and mountainous regions which may still be active.