A major U.S. military presence has long existed on the tiny western Pacific island of Guam, but now it's suddenly in the crosshairs of the North Korean regime.
But why Guam? And why has it quickly become known as the tip of the spear of U.S. defense?
The U.S. territory, located 2,100 miles from North Korea, is home to some 160,000 people, 7,000 of which are American military personnel. It also houses strategic bombers and U.S. Navy ships, all within striking range of hot spots, like North Korea.
But Guam's importance to America's Pacific defense capabilities have left it vulnerable to being caught in the crossfire of the North's leader, Kim Jong Un.
On the island, sits Andersen Air Force base, which houses a helicopter squadron and Air Force bombers, including the B-2 stealth bombers -- bombers which flew over South Korea in a show of force last month after a North Korean ballistic missile test.
Despite North Korea's threats, many on the island feel reassured and protected by the military.
"It's actually been scary since yesterday. We're trying to plan out if there's going to be an emergency and things like that," said Kate Quiambao, who has lived on the island her whole life.
History shows it's not the first time North Korea has threatened Guam since the United States took control of it in 1898 from Spanish settlers. During the Vietnam War, the Air Force sent 155 B-52 bombers to Guam to hit targets in Southeast Asia.
Guam was also a refueling and transfer spot for people heading to Southeast Asia, and many refugees fleeing Saigon were evacuated through Guam.
During World War II the island was occupied by Japan. After the war, the U.S. military turned the island into a vital military outpost in the region.
In 2013, state media reported Kim ordered his military to prepare plans on launching strikes on U.S. military bases in Guam, Hawaii and South Korea, but then changed his mind.
In August of last year, the North's foreign ministry warned that all U.S. military bases in the Pacific, including Guam, would "face a substantial attack." But no attacks took place.
The U.S. Marine Corps has plans to move about 5,000 troops to Guam in the coming years as part of an effort to reduce its presence on Okinawa, Japan.
It's important to note that Guam is armed with the U.S. Army's anti-missile defense system, known as THAAD, which has been tested and retested successfully to intercept missiles. U.S. intelligence reports show North Korea has around 60 ballistic missiles.