This twisted helix is full of gas from dying stars. It was taken in 2002 and is a mere 690 light-years away.
New baby stars will emerge from this pictured eerie hydrogen gas, which acts like a sort of egg that incubates new stars. These "space serpents" are part of the Eagle Nebula.
Can you see the dark matter? It's elusive because well, it's impossible to see. But there's a lot of it here, with some hot gas in the core of galaxy Abel 520.
The iconic Horsehead Nebula was captured in astonishing detail to celebrate Hubble at 23.
Here several moons cast shadows on Jupiter. The black spots you see are not shadows but Jupiter's largest moons Io, Ganymede and Callisto.
Here is a giant mosaic of the Crab Nebula, remnants of a dying star six-light years across.
Another nebula, this one is called the Cat's Eye, you can see why. It's one of the first of its kind discovered.
Hubble captured the true shape of the Ring Nebula in this colourful image. It's part of a constellation called Lyra and is 2,000 light-years away.
Part of the constellation Sagittarius, this image of the Omega/Swan Nebula was taken in 2003 and is an active star-forming region.
Saturn is pictured at various wavelengths as the planet is tilted 27 degrees towards Earth, its maximum tilt.
These spirals of dust are said to imitate the "Starry Night" art work by Vincent Van Gogh's painting.
A multi-wavelength view of a nebula, a star cluster and far-away galaxies.
The Whirlpool Galaxy shows bright one stars being born (in red). Dust at the centre of this galaxy may be feeding a black hole.
Two spiral galaxies passing each other.
To end with, an image celebrating Hubble turning 21, which is called "Rose of Galaxies" due to the beautiful flowery shape of the larger spiral galaxy.