Game of Thrones season 6 episode 5 explained where the White Walkers came from

Damnit, Leaf!

Though it was dealt with pretty swiftly - probably because of certain other incredibly dramatic moments to come in the episode - Game of Thrones gave us an important piece of Westeros history tonight: exactly where the White Walkers came from *spoilers ahead*.

In a flashback, Bran saw Leaf and the Children of the Forest plunge a shard into the chest of a man, making his irises go blue and presumably turn into the first ever White Walker.

"It was you, you made the White Walkers," Bran said to Leaf when returning to the Weirwood tree.

"We were at war, we were being slaughtered," she defended, "our sacred trees cut down, we needed to defend ourselves."

"From who?"

"From you. From men."

Leaf clearly felt guilty over her part in creating what would turn out to be a huge threat to every single race in the Seven Kingdoms, and later in the episode gave her life for it, blowing herself up and taking a load of Walkers with her to provide Bran and Meera to escape.

It wasn't her sacrifice that had fans blubbing however, it was Hodor's - there's more on that here.