By Jonathan Beale
BBC News, Alaska
Hidden deep in the Alaskan wilderness lies America's latest weapon in its war on terror.
State of the art technology is sited at the military base at Fort Greely
The heavily defended Fort Greely is the centre of America's missile defence shield.
A 50-year-old Cold War relic, it has been revived to defend against 21st-Century enemies using 21st-Century missiles.
It is now the site of state of the art technology aimed at intercepting any ballistic threat to the United States.
This is the first time the US has shown the rest of the world the nerve centre of the project dubbed "the Son of Star Wars" by some.
Officially called the National Missile Defence programme, the aim is to develop and deploy a defensive screen for the whole of the US, which would have the ability to track and destroy incoming ballistic missiles.
In the control room at Fort Greely, where America would launch its ground-based missile interceptors, operators linked up to satellites in space and radar on the ground can respond within seconds.
Lieutenant Colonel Ted Hildreth, of the 49th Missile Defence Battalion, says: "I don't think anyone has crystal ball clarity where the threat is, where it will come from - but know that our crews are trained, ready and prepared."
A clock on the wall of the control room, showing the time in Korea, indicates where America believes at least one threat exists.
Lieutenant General Henry Obering, director of the US Missile Defence Agency, confirms that the two primary concerns for the US military are North Korea and Iran.
"I believe that a threat consists of two things: one is intent and the other is capability," he says.
"Historically of course, there has been hostile intent on the part of the North Koreans and there have also been hostile intentions by the Iranians."
Tests have already been carried out on the missile defence system. The challenge has been likened to hitting a bullet with a bullet in space.
The US military claims most interceptions have been successful.
But these tests have taken place under controlled conditions - and it is a far cry from ensuring that these missiles would hit their target if there were to be a surprise attack.
The critical paradox is this: the US has to knock down every missile but their enemies only have to penetrate the shield just once.
Nevertheless, America is pressing ahead with its missile defence shield at an unprecedented pace.
At Fort Greely, the military is installing one missile silo every month.
And it is not just in Alaska - the US also hopes to build a radar station in the Czech Republic and to site interceptors in Poland.
The US defence system is designed to intercept incoming missiles
This has sparked vehement opposition from Russia, which sees America's actions so close to its borders as offensive, not defensive.
But America, its old Cold War adversary, is not backing down.
Washington argues its system is not designed to defend the US from Russia, but rather to be effective against attack from countries with limited missile programmes, such as North Korea and Iran.
In 2002, the US withdrew from the 1972 Anti-Ballistic Missile Treaty it signed with the Soviet Union.
Russia protested over the move, but has successfully tested a modernised anti-ballistic missile of its own.
Just down the road from Fort Greely, in the small town of Delta Junction, some locals are far from convinced that they are now safer.
"I hope it works, but I'm not going to hold my breath," says one man.
Another points out that the point of building a defensive system is to save the US from having to go to war.
But the unanswered question remains: is America's missile defence shield really a guarantee to protect the homeland from any future threat of attack?