That is a portion of our neighbor galaxy Andromeda.
It is over 2 million light years away.
In just this portion of Andromeda, there are 100 million stars.
The universe contains over 100 billion galaxies like Andromeda.
The image above can't really do this justice because it was assembled into a mosaic image using 7,398 exposures taken over 411 individual pointings. It's a mammoth 1.5 billion pixel image (69, 536 x 22, 230) and requires about 4.3 GB disk space.
Trying to grasp all of that brings on the definition of "awe."