Tomorrow, Apple will open the doors to its new Apple Park (Campus 2) for the first time to reveal the iPhone 8. The announcement will take place in the park’s “theater” – a masterpiece that features the world’s largest freestanding carbon fiber roof.

Buzz surrounding the enormous roof began last year. According to Apple Insider, architectural renderings originally seemed to indicate that the roof would be made of the company’s signature aluminum or steel, but instead, architects opted for composites.

The circular roof weighs 80 tons and is slightly above 140 feet in diameter. It is made up of 44 identical radial panels, each 70 feet long and 11 feet wide. Dubai-based Premier Composite Technologies, which has created some of the largest composite architectural structures in the world, created the roof before shipping it in pieces to the Apple campus in Cupertino, Calif. The whole theater itself, a subterranean auditorium, will be 120,000 square feet and will have a capacity of 1,000 seats.

The theater has 360-degree curved glass-fronted walls and central courtyard as well as a 1,000-seater auditorium, a gym and 300,000 square feet of research space. The glass structure is also fitted with solar panels.

To see an overhead view of the entire campus, check out this video taken by drones last week.