Apple opened gates to its undeniably spaceship-themed campus for the launch of its three latest iPhones today and, even though it’s not complete, it is impressive and overwhelming in scale.

The company took over the 175-acre Cupertino campus from Hewlett-Packard when it was mostly covered in concrete.

Apple’s approach, like its technology, was different.

a circular building designed to house 12,000 employees and created in collaboration with Foster + Partners. While four storeys are visible above the ground, it also has another three stories below it.

The giant circle delivers 260,000 square metres of office space, much of it open-plan, though not all of it is being used yet. While some engineers and security staff moved into Apple Park earlier this year, cardboard boxes remain visible from the street in some offices.

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It’s unlikely that Apple is wasting power on empty spaces, however. The building features one of the largest solar panel installations in the world atop its roof, and features a smart heating and cooling system that uses natural airflow from outside.

In one of his last interviews in 2011, Apple co-founder Steve Jobs described his vision for the energy-efficient, uniquely designed Apple campus and why he knew it wouldn’t be the easiest building to construct.

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“It’s a circle, so it’s curved all the way round. This is not the cheapest way to build something,” he said.

“Every pane of glass in the main building will be curved. We have a shot at building the best office building in the world. I really do think that architecture students will come here to see it.”

At the centre of the massive circular building is a 30-acre courtyard that will feature apple, apricot and olive orchards, a herb garden, and a sizeable pond.

Apple is still working on its landscaping, however, and it is a massive task.

Chief executive Tim Cook revealed the company had planted 9000 trees on the property, all native and drought-resistant, and the effect is striking.

It looks like the huge building is hiding in a forest — or like one has just landed in a forest — rather than sitting on land reclaimed from typical Silicon Valley office parks.

Though Apple has yet to throw the doors open to its spaceship-shaped control centre, the media was granted access to its adjacent Steve Jobs Theater today, a custom-built 1000-person hall for presentations and demonstrations.

Apple co-founder Steve Wozniak, who took a seat at the front of the iPhone launch before the rest of the crowd, gave a glowing review of the new campus, and said his fellow company co-founder would have approved of what it had become.

“The all-glass structure was an architectural style that Steve (Jobs) was very much into,” he said. “It looks just amazing.”

Like the ‘mothership,’ the theatre is circular and completely transparent thanks to walls made of curved glass. You have to appreciate the elbow grease and cloths it must take to keep the theatre, and its larger office building, clean.

Two white marble staircases and one spinning, circular lift descend to the theatre level, where comfortable seating hides media-friendly power points beneath the chairs.

Apple is expected to move more employees into Apple Park by the end of the year.

Jennifer Dudley-Nicholson travelled to Cupertino as a guest of Apple.