It's been a long time coming, but Apple will soon open its massive $5B "spaceship" campus, a massive 175-acre space in Cupertino that the late Steve Jobs once called "the best office building in the world."

The campus, designed by architect-superstar Norman Foster, is set to finish by the end of 2016. But what does the construction site look like now? Recent drone footage released this week captured how far the project has come:

The centerpiece—a doughnut-shaped four-storied circular building of roughly 2.8M SF—has mostly been completed. The footage shows that workers are installing panels of curved glass that will make up the building's walls. The roof will be eventually covered with solar panels.

The development is gigantic. The area, which was once home to Hewlett Packard, will even include a 1,000-seat auditorium for Apple's corporate events, a fitness center and parking space. 

Of course, there's still a lot of work to be done till the building's grand opening. When the campus is complete, the buildings will be surrounded by elaborate landscaping and greenery, where Apple workers can enjoy lunch and relax.