9. THE WALL
The Wall lies north of the Gift, built thousands of years ago, the wall defends the rest of Westeros from wildlings (or did) and the White Walkers. It stands at 300 miles long (though Sam does incorrectly say 500) and 700 feet high, with 19 castles lining it, though only three are manned: Castle Black, the Shadow Tower and Eastwatch, peopled by brothers of the Night’s Watch.
In the beginning of the series, we can assume there were several hundred men across the wall. After the Great Ranging led by Jeor Mormont back in season 2, the Night’s Watch lost hundreds of brothers, and in the aftermath of the Battle of Castle Black in the season four episode, “The Watchers of the Wall,” the Night’s Watch has an estimated 70 or so brothers. Jon Snow left it all to Edd, who has quite the task ahead should the White Walkers decide to show up.