www.youtube.com/watch?v=uv5Uf7pJ9dMOn January 11, 2007, Fengyun 1C, a Chinese weather satellite, was destroyed by a Chinese anti-satellite missile. This created the largest number of trackable debris items of any single event, with over 3,000 objects larger than 10cm created, approximately 20% of all of the objects orbiting in low-Earth orbit, although a sizeable number of pieces have already reentered the Earth's atmosphere.
These all pose a threat to other orbiting satellites, as even a small object travelling at 28,000km/h (17,000mph) can cause substantial damage. In fact, in January 2013, the Russian "BLITS" satellite was badly damaged by a piece of Fengyun-1C, and the International Space Station has had to take a evasive action to avoid a collision on more than one occasion.