An old fan theory has been confirmed in the new chapter 1115 of the One Piece manga, about there being continents in the series that are submerged.
The geography of the One Piece world has always attracted attention because excluding the Red Line, the world only consists of small islands and the rest is water.
Now, chapter 1115 of One Piece has suddenly revealed, there are giant continents sinking into the sea when the water level rises 200 meters. Vegapunk states that Poneglyphs are historical records that tell of a great battle that took place in the Void Century.
During the broadcast of Vegapunk's message to the world, he revealed that a major war between Joy Boy and the World Government between two types of ideals had taken place, but the doctor did not know who was truly right. Joy Boy was defeated but when the war ended, the whole world changed, as the sea level rose 200 meters.
Vegapunk said that Joy Boy's failure marked the end of the Void Century.
As we saw before, the use of ancient weapons caused sea levels to rise. This means that the government's use of them in the confrontation with Joy Boy is the reason why the sea level has risen so much. The continents that existed 1000 years ago have been completely submerged, and the islands we see are simply a small portion of those continents that have not yet been submerged.
If you connect the dots, the construction of Noah's Ark in the Fishman Island arc now makes sense. Because it can be a shelter for people when the sea level is increasing a lot.
Vegapunk also revealed that the ideal war is not over yet, and the ancient weapons Pluton, Poseidon, and Uranus will still be very important in this war.
Furthermore, this chapter confirms that the Five Elder Stars Saint Mars are users of Conqueror's Haki. The chapter ends by showing Imu's face but it's still dark so there's probably no way to tell what he really looks like.