President Obama is creating the largest protected area on the planet. Here's what you need to know about where it is, what it's for and how to pronounce it. (Gillian Brockell/The Washington Post)

President Obama on Friday created the largest ecologically protected area on the planet when he expanded a national marine monument in his native Hawaii to encompass more than half a million square miles.

The president more than quadrupled the size of the Papahanaumokuakea (pronounced “Papa-ha-now-moh-koo-ah-kay-ah”) Marine National Monument to 582,578 square miles of land and sea in the Northwestern Hawaiian Islands.

President George W. Bush established the monument a decade ago, but Obama’s action Friday underscores the high priority he has placed on issues of conservation and climate change in his second term. The president has now used his executive authority under the 1906 Antiquities Act to protect more than 548 million acres of federal land and water, more than double the set-asides of any of his predecessors.