Australia has unveiled plans to create the world’s largest marine reserve in 16 million acres of the Indian Ocean, 2,500 miles off the nation’s southwest coast. The Heard Island and McDonald Islands Marine Reserve will be twice the size of Switzerland and will protect one of the world’s most pristine marine environments from exploitation, including fishing and oil and mineral extraction. The Antarctic waters of the reserve-to-be are home to many important species, including the endangered southern elephant seal, the sub-Antarctic fur seal, and the Patagonian toothfish. Heard Island is home to Big Ben, Australia’s highest mountain and only active volcano; McDonald Island has such a steep coastline that only two boats have landed there since it was discovered more than a century ago. Although there is no commercial fishing in the area, the Australian government estimates that poachers net 2,200 tons of fish in southern waters every month.