Game of Thrones appears to be teasing a Northern rebellion and a divided Westeros in the series finale. The penultimate episode of Game of Thrones angered some fans, but it definitely moved things forward - King's Landing fell, Daenerys went full-blown Mad Queen, and Cersei finally died in the rubble of the Red Keep while trying to escape. With Cersei gone and Dany crazy, it's clear that the finale is going to be all about the conflict between Jon and Daenerys, and that could well mean a Northern rebellion.
As it stands, King's Landing is in ruins, but presumably, Daenerys is still planning on being Queen of the Ashes. However, her actions in "The Bells" will have turned Jon and Tyrion against her, leaving her alone - with her armies, but with no clear advisers or Westerosi allies. Before his death, Varys sent out letters proclaiming Jon as the rightful King, and while it's not clear who he sent them to, Sansa is already aware. It's highly likely that she decides to use this information to rally the North to her, and to attempt to overthrow Daenerys and put Jon on the Iron Throne. He may not want it, but a Northern rebellion makes a whole lot of sense for the final episode - especially considering one particular scene in the penultimate episode.
As Cersei was attempting to flee King's Landing, she lost Qyburn, the Mountain, and the Queensguard, until she was seen alone in her map room with the castle coming down around her. As she rushes across the map on the floor, the dragon roars, and the floor cracks, with one clear break right across her painted map. This massive crack runs from one side of the map to the other, just below the Neck, effectively splitting the map (and the land) into a Northern and a Southern half.
This divide may have been random, of course, and the crack simply shows that Cersei's big plans to rule are broken - and literally falling down around her. However, it may also be a hint. This season has been big on callbacks and references to season 1, and the decision to have a single, obvious line across Westeros rather than seeing a larger part of the floor caving in may have been deliberate. Having a Northern rebellion also makes a lot of sense from a storytelling perspective; not only are Jon and Tyrion now anti-Daenerys, but Sansa is currently holding the North - and she's never been a fan of the Dragon Queen. She's also closely connected to both Jon and Tyrion, and there are plenty of characters left scattered across Westeros whose stories need a proper conclusion in the final episode.
Having them rebel would be a perfect way to bring everyone back together, without relying on a simplistic "where are they now" wrap up at the end. This crack may even be hinting at where that final battle will take place - as everyone comes together somewhere along that line. It would be a beautiful reference to the history of the Targaryens, as one of the major battles of Robert's Rebellion took place along that line, near the Inn at the Crossroads. (Which, should the Game of Thrones series finale end up there, would allow fan-favorite Hot Pie to make his own final appearance.) If this crack is a hint at things to come, it could mean that Game of Thrones is going to end without a new ruler of a unified Seven Kingdoms. Instead, the show may end with two Kingdoms, one in the North (ruled by the Starks), and one in the South (ruled by another claimant to the throne, whether that is Jon, Gendry, or someone else altogether).
A Northern Rebellion and a split Kingdom would certainly fulfill Dany's plans to break the wheel, but it would likely do so at the cost of her life, as few fans are expecting her to make it through the finale at this point. Of course, there's no way of knowing whether that crack was a hint, or if it was just part of the destruction of King's Landing. But it would be poetic for the Stark, Baratheon, and Lannister houses to rebel against the Targaryens just as one of them becomes a bit mad. It happened with Robert's Rebellion and it can happen again to close out the Game of Thrones story.
Game of Thrones' series finale airs Sunday, May 19 on HBO.