(CNN) -- Fiery asteroids smash into Earth's atmosphere at such a stunning rate, it's a wonder we don't see fireballs raining down from the skies more frequently. A new NASA map from the space agency's Near-Earth Object Program, reveals that more than 556 space rocks smashed into the atmosphere over a 20-year period between 1994 and 2013. The good news is most are small and harmless fireballs that disintegrate when they hit the atmosphere, the space agency said in a press release. An obvious exception occurred on February 15, 2013, when an asteroid as large as 55 feet in diameter with a mass of up to 10,000 tons crashed to earth in the Urals region in Russia, streaking through the morning sky in Chelyabinsk before landing in a fiery explosion that injured more than a thousand people and caused an estimated $33 million in damage. More via CNN.com.