Actually, there's a theory about the 3 DF that created the world like it is today, and they are the only 3 fruit that can undo this.
Kid's fruit in this theory gave magnetism to the Grand Line Islands, Law's fruit separated giant portions of earth to the grand line and it became the islands there.
And the third fruit is an addition by me, the Red Line is made of something that we don't know what exactly it is. If we confirm Luffy's DF as a legendary Resin fruit, it could be the fruit that created the Red Line 800 years ago, and it could explain the "indestructible" factor.