President Barack Obama will expand the size of the Papahānaumokuākea Marine National Monument in the Pacific Ocean to over 580,000 square miles from 140,000 square miles. The sanctuary, which contains thousands of marine species, stretches across the Midway Atoll and Hawaii, and will become the world’s largest protected marine area, The New York Times reports.

Obama will travel to Midway Atoll next week to mark the vast expansion. First, he will address the Pacific Island Conference of Leaders and the IUCN World Conservation Congress in Hawaii, and then later in the week he will fly to Papahānaumokuākea to mark the designation and “highlight first-hand how the threat of climate change makes protecting our public lands and waters more important than ever,” according to the White House.

larger than 46 states

The expansion will make Papahānaumokuākea the largest national monument in the US. The marine park will be larger than 46 states, as well as 7 times larger than all other national marine sanctuaries combined. Currently, Papahānaumokuākea is home to more than 7,000 marine species, including endangered whales and sea turtles and the longest-living marine species in the world — black coral, which have been found to live longer than 4,500 years.

The marine reserve is also important as a sacred place to Native Hawaiians. According to UNESCO, which designated the reserve as a World Heritage Site in 2010:

The area has deep cosmological and traditional significance for living Native Hawaiian culture, as an ancestral environment, as an embodiment of the Hawaiian concept of kinship between people and the natural world, and as the place where it is believed that life originates and to where the spirits return after death. On two of the islands, Nihoa and Makumanamana, there are archaeological remains relating to pre-European settlement and use. Much of the monument is made up of pelagic and deepwater habitats, with notable features such as seamounts and submerged banks, extensive coral reefs and lagoons.

Within the monument expansion area, there are shipwrecks and downed aircraft from the Battle of Midway in World War II, a battle that marked a major shift in the progress of the war in favor of the Allies.

The expansion of the marine reserve is the latest example of Obama’s use of the 100-year-old Antiquities Act, which grants him the authority to preserve places of ecological, historical, or cultural significance. The White House says that Obama has protected hundreds of millions of acres during his administration, more than any other American president.