Ross Sea Marine Reserve
The Ross Sea in Antarctica is home to the world's largest marine reserve, covering 598,000 square miles — an area twice the size of Texas — in the Southern Ocean. It's also one of the newest nature reserves, established in October 2016 by the Commission for the Conservation of Antarctic Marine Living Resources, a group of 24 countries that oversees the water around the continent.
The Ross Sea is also known as the "Last Ocean" because it's one of the last remaining stretches of ocean that has not been harmed by humans or damaged extensively by overfishing, pollution or invasive species, according to the Antarctic and Southern Ocean Coalition. The extremely remote area is inaccessible by boat most of the year, which helps preserve it, though the rising demand (and price) for seafood and the low cost of fuel may tempt some fishermen to brave the journey.
National Geographic reports: "Its nutrient-rich waters are the most productive in the Antarctic, leading to huge plankton and krill blooms that support vast numbers of fish, seals, penguins, and whales. Some 16,000 species are thought to call the Ross Sea home, many of them uniquely adapted to the cold environment."