This series of Hubble Space Telescope images reveals the breakup of an asteroid over a period of several months starting in late 2013. The largest fragments are up to 180 meters (200 yards) in radius.
This is the first time ever! NASA’s Hubble Space Telescope has recorded the break-up of an asteroid, P/2013 R3, into as many as 10 smaller pieces. The crumbling asteroid was first noticed on Sept. 15, 2013.
It is not known why it desintegrated into various pieces. You will find some hints here.