Much of what we know about the universe is thanks to pictures taken by the Hubble Space Telescope which was launched by Nasa in 1990
Plans to build a telescope that could be launched into deep space began in the late 1970s, soon after the first space mission.
Twelve years and US$2 billion later, Nasa launched the Hubble Space Telescope. It was to dramatically alter our perceptions of what we know about the universe and our place in it.
The Hubble didn't get off to an easy start. Almost as soon as it was launched, there were problems with the big mirror. It took two years to repair, but it was worth the wait.
With the telescope properly set, the Hubble began sending back incredible images. It gave us the first awe-inspiring pictures of cosmic creations such as black holes.
The image of the Eagle nebula - a massive cloud of gas and dust in which stars are formed - is one of the most memorable pictures captured so far. It shows bright points of light within three huge towering columns of gas, each one larger than our own solar system.