Warning: spoilers ahead for the series finale of Game of Thrones!
Poor, poor Daenerys. After eight seasons spent conquering her way across the Game of Thrones universe, she never even gets to sit on the Iron Throne in the series finale. She does, however, get to tell an interesting story about its origin, before Jon stabs her and Drogon decides to torch the uncomfortable symbol of power, ensuring no one will ever sit on it again. The Mother of Dragons tells Jon that her brother, Viserys, once told her that the Iron Throne was made of the 1,000 swords of Aegon the Conqueror's enemies. As a little girl, she couldn't fathom what that many swords would look like, but as she stands in front of the throne, she finally gets to see the monstrosity for herself.
There seems to be some debate on exactly how many swords made up the throne, but Daenerys's story adheres to what's stated in the book series. Aegon the Conqueror is said to have forged the Iron Throne from the swords that were dropped at his feet as a sign of fealty after the War of Conquest ended. It took 59 days to forge the Iron Throne, and the swords were heated by the breath of a dragon known as Balerion the Black Dread. If you're thinking this sounds like an incredibly uncomfortable seat, that was always Aegon's intention. He believed that the chair should be uncomfortable as a reminder of the weight of power that comes with the position of ruler. He believed that no king should ever sit easy.
His philosophy doesn't exactly pay off. Despite the Iron Throne being notoriously painful to sit on, everyone from the Mad King to Cersei to Daenerys covets it. What Aegon intended to be a symbol of responsibility became nothing more than an object that represented oppression and greed. Since he's also the person who first united the Seven Kingdoms, there's something deeply sad about his story. Yes, he was a conqueror, but his ultimate goal was to create a unified kingdom under a just rule. Instead, he set in motion the very wheel that Daenerys is obsessed with breaking. In many ways, Daenerys follows in his footsteps, and makes many of the same mistakes. As she makes clear in the decimated Throne Room, she didn't learn the moral of the story because she was too blinded by a desire for power.
Seeing Drogon destroy the Iron Throne is a reminder that it was dragon-forged. When he torches Westeros's seat of power, he also symbolically marks the official end of the Targaryen reign. Unless Jon ever decides to return and take over as leader from Bran — which seems highly unlikely — there will never be another Targaryen ruler. The end of the throne is truly the end of an era for the Seven . . . er, Six Kingdoms. Aegon is responsible for creating the Throne, and Daenerys's dragon is responsible for destroying it. Without the Iron Throne, Westeros is set to try a new way of ruling that doesn't involve conquering or sitting on a literal throne of swords. Instead, they're trying something a bit more democratic and turning their backs on the Targaryen ideas of predestination and royalty. Whether or not this will lead to a happier future is unclear, but at the very least no one else will have to figure out how to sit on the Iron Throne without risking bodily harm.