The Cassini mission officially came to an end on Friday, September 15th. NASA commanded the spacecraft into a controlled plunge into Saturn's atmosphere so that it would burn up upon reentry.
Although it was an emotional time for those involved with the project, it was the right decision to make. The spacecraft was running out of fuel, and if NASA didn't dispose of it how they did, there would be a risk of it crashing into one of Saturn's potentially-habitable moons.
Cassini snagged final measurements and photographs just before it disintegrated in Saturn's atmosphere, and in this video, you can see many of those last shots; the detail is staggering.
Cassini is now a part of Saturn, and we won't return to the Saturnine system for many years to come. Fortunately, we learned so much about the system from this mission that we know exactly where to send our next exploring spacecraft.