The Mariana Islands, shown in orange, is a Western Pacific archipelago just north of the equator, about 1,500 miles from Asia and nearly 4,000 miles from Hawaii. It's made up of two U.S. territories: Guam and the Commonwealth of the Northern Mariana Islands. Use the map controls for a better view and zoom in to see more detail.
The U.S. has used the islands for military training for decades, often leaving behind waste and wreckage. Now, the military presence is going to sharply increase because of a deal the U.S. made with Japan to move about 5,000 Marines from Okinawa to Guam.
The Navy recently got approval to increase its use of undersea sonar and explosives across nearly a million square miles surrounding the Mariana Islands. There's relatively little data on marine mammals in the region, making some fear that the Navy is underestimating the harm to marine mammals.
The Navy wants to use the northern part of Pagan for a bombing range. The island used to be home to dozens of indigenous people who lived off the land but were forced to leave in 1981 due to a volcanic eruption. Many of those former residents say they want to move back to Pagan but worry the increased military presence will make it impossible.
Farallon de Medinilla is a small, uninhabited island north of Saipan that has been used as a bombing range since 1971. The U.S. has the right to bomb the island for 100 years, in exchange for giving commonwealth residents U.S. citizenship. The military recently increased the intensity of bombing by 300 percent.
Just over 3,000 people live on Tinian and have been expecting the military to build a base on the northern two-thirds of the island. Instead, the military wants to add training areas, including a bombing range, that residents fear could taint their water supply and destroy their tourism industry.
Guam is already home to Navy and Air Force bases, and will soon have a Marine Corps base as well. Activists are worried about a plan for a live-fire training range will limit access to a national wildlife refuge for birds and other endangered species. Zoom in to see Anderson Air Force base and the Naval Base on Guam.