On Thursday, President Obama created the world’s largest ocean reserve. The new reserve, an enlargement of the existing Pacific Remote Islands Marine National Monument, nearly quadruples the total amount of US ocean territory that’s protected from commercial fishing, oil drilling, and other activities. Previously, the monument — a cluster of reserves surrounding seven uninhabited islands south and west of Hawaii — covered about 86,888 square miles. The new monument will cover nearly 490,000 square miles in total, with the gains coming from extending the borders to 200 miles off the coasts of Wake Island, Jarvis Island, and Johnston Atoll. This is as far as the US government is permitted to protect, according to international law.