The Broken Seal

From WikiUeda

The Broken Seal is the name of the area beyond a mystic door at the southern tip of the world in Shadow of the Colossus. The Save Shrine in this area (and the area itself) is notable for being the only off-limits area in the game's outset; in fact, it can only be accessed after defeating fifteen colossi. The sixteenth and final colossus, Malus, lies beyond this area, across a canyon and atop a gigantic mass of land.

In the middle of this area is a bridge on the verge of collapse - any weight at all will cause it to crumble. It is here that Wander is separated from Agro.