Over the last half millennium, societies around the globe competed to divide up the world’s land. Nearly every square inch of soil outside Antarctica is now owned and tucked within national borders. But the oceans have largely been spared that fate. There were times throughout history when countries tried to gate and regulate the seas, but they were too vast to be controlled for long periods. During the Cold War, as technology made it far easier to imagine partitioning the world’s waterways and seabeds, great powers avoided an unrestrained race to grab the oceans.