Were has the biggest asteroid landed? How much damage did it do and how far?

Question: Were has the biggest asteroid landed? How much damage did it do and how far?
- Keywords:
  earth,
  space,
  universe
Asked by gangdelf to Joe on 11 Mar 2014.
- Joe Sweeney answered on 11 Mar 2014:
  
  The only way we can estimate is from the size of the crater it leaves behind, so it seems the biggest asteroid impact happened in South Africa, at a place called Vredefort. The crater was about 300 km wide, suggesting the asteroid was about 7 km in diameter. That’s nearly 5 miles wide!

Question: Were has the biggest asteroid landed? How much damage did it do and how far?