VY Canis Majoris is a red hypergiant star located in the constellation Canis Major. At between 1800 and 2100 solar radii (approx 2.7 billion km), it is currently the largest known star in terms of relative size to our own sun (although not in terms of mass).
The size is beyond comprehension.
If you Canis replaced our own star, it would engulf everything up until Saturn.
It's width, as compared here, is just short of all the planets to Uranus.
It's BIG!via www.flickr.com