BRUSSELS (AP) — NATO's future goals might be hazy but work is progressing steadily on the U.S.-led alliance's new home-to-be.

The environmentally-friendly headquarters complex, expected to cost 750 million euros ($1 billion), should be ready by the summer of 2016, officials told reporters on a media tour Wednesday.

"It's time for us to move on," said NATO spokeswoman Oana Lungescu.

In 1967, the North Atlantic Treaty Organization moved into its current headquarters on the outskirts of Brussels, a location that was supposed to be temporary. Now officials say the foundation is crumbling, there are too many access points from a security standpoint and meeting rooms are too cramped.

Since it's been in Brussels, NATO's membership has grown to 28 countries with a total of 4,200 military and civilian personnel in the city.

"We need to leave, because this building has outlived its usefulness," said NATO assistant deputy secretary general Matthew Klimow.

In December 2010, work began across the road on a new headquarters. When finished, it will have eight long wings connected to a central space and only three entrances: one each for staff, journalists and VIPs.

Mobile phones will work everywhere and windows will convert sunlight to energy that can be stored underground and tapped in the winter.

Some have questioned whether an organization founded to counter the Soviet threat has a role in today's world but Lungescu said the fact that members agreed to build the alliance a new home is "a vote of confidence for the future of NATO."