Liam Neeson continues his ass kicking streak by beating all other competitors at the box office this weekend. Unknown took the top spot with $21.7 million, which is a little less than Neeson’s previous solo actioner, Taken, but still strong for the usually horrible mid-winter season. Second place went to the teen action movie I Am Number Four with $19.4 million. Gnomeo and Juliet remained in third place with another $19.2 million. Last week’s number one, Just Go With It, fell down to fourth with $18.5 million and the other new release, Big Momma’s: Like Father, Like Son rounded out the top five with $16.3 million. Justin Bieber had a massive drop off from the previous week, going from second to sixth with $13.3 million. Other than those, there wasn’t a lot of other movement in the top ten.