One Piece

The Calm Belts are vast, impenetrable expanses of tranquil waters that serve as natural barriers to the Grand Line. These waters, devoid of currents and winds, act as nesting grounds for the colossal Sea Kings, making any attempts at navigation perilous. The only haven for travelers is Reverse Mountain, a treacherous passage into the Grand Line, fraught with its own dangers. While the Marines have found a way to traverse the Calm Belts using ships lined with Seastone to avoid detection, the risk of encountering the monstrous Sea Kings remains ever-present.

An aerial view of the eerily still waters of The Calm Belts, with the shadowy silhouettes of enormous Sea Kings lurking below the surface, under a sun-soaked sky.