MIAMI (CBSMiami) — Scientists reveal an asteroid dubbed by some as a “city-killer” came closer to the Earth than the moon this week.

To make this even scarier, scientists say they had no idea the 328-foot wide asteroid was coming our way.

While much smaller than an extinction-level asteroid, which are usually at least half a mile wide, it was still big enough to cause major destruction.

The space rock, named Asteroid 2019 OK, came hurtling toward Earth at a speed of nearly 15 miles a second, before flying past on Thursday.

Astronomers first detected it last week but say it posed no immediate threat.

However, they admit they had no idea the giant rock was headed our way, because it came from the direction of the sun and only became visible a few days ago.