In Game of Thrones, perhaps the most fearsome warrior in all of Westeros is Gregor Clegane, known as the Mountain That Rides, or the Mountain. He's almost 8 feet of muscle and rage and carries a 6-foot sword ... with one hand. It's unsurprising that the man who currently plays him is tall and strong. But actor Hafþór Björnsson is much, much stronger than most.
Bjornsson, who probably could wield a 6-foot sword with one hand, has recently won Europe's Strongest Man competition. According to MTV,
he took on all challengers and left none standing, placing in first in three major categories: deadlifting; atlas stones; and the forward hold of Thor’s hammer (yes, seriously).
In addition, he placed second for the title of World's Strongest Man, which technically makes the Game of Thrones actor the second strongest man in the world.
He's also the third actor to play Gregor Clegane. The Mountain was originally played by Conan Stevens, who left Game of Thrones to take a role in The Hobbit (how awesome is that?). In season two, the character was played by Ian Whyte (the 7'1" Whyte continues to appear in the show as—what else?—a giant).
According to Wikipedia, Bjornsson is 6'9" and weighs almost 400 lbs. He's also stronger than you.
Check out his moves here: