The Unknown Zone: Asteroids...10 largest Earthly hits and their dangers

The asteroid know as 2012 DA14 narrowly missed the EArth in 2013, the closest asteroid flyby on record. But the planet has not always been so lucky.

Earth's craters are enduring testaments to direct asteroid hits. And though millions—in some cases billions—of years of erosion have made it difficult to determine the exact size of the meteorites, there is a general scientific consensus around the world's largest craters, which mark the largest asteroid impacts.

Judy Sellins and Dave Turco will go over the top 10 biggest asteroid strikes and what impact it had on our world and it's inhabitants.