Apple employees will begin moving into a new campus in Cupertino, California this month.

The new Apple headquarters, named Apple Park, is a single ring, about a mile in circumference, set in a large campus that will be covered in plants and trees.

Late Apple CEO Steve Jobs once said that the new campus was "a shot at building the best office building in the world."

It will house 13,000 employees on over 2.8 million square feet of office space. Apple employees will enjoy fruit trees, a massive fitness center, and a workspace that's been carefully overseen by Jony Ive, Apple's chief design officer.

The Apple HQ has been compared to a UFO and the Pentagon — and after about $5 billion in costs, according to Apple CEO Tim Cook, it's ready to open.

Here's a look at Apple Park over the past five years, and what still needs to be done:

Here's the entire campus, as of March 2017, in one shot.

(Apple (Apple)

This is an architect's rendering from the beginning of the process that was made public in 2013.

The engineers are expected to work at a nondescript office in Palo Alto, California, close to the corporate headquarters (City of Cupertino)

Steve Jobs originally announced the plans for Apple Park at a Cupertino city council meeting in 2011. It ended up being his last public appearance.

(YouTube/Cupertino (YouTube/Cupertino)

"It's a little like a spaceship landed," Jobs said. Watch the entire video — it's a little bit like an iPhone launch:

Apple Park is right down the street from Apple's current campus, Infinite Loop, and is significantly larger.

Apple's architect is Foster + Partners.

This is the most detailed depiction of where everything is located. Note the fairly large fitness center in the northwest corner of the lot, the ample parking near the freeway, and the corporate auditorium with direct access from the road.

(Foster + Partners / Cupertino (Foster + Partners / Cupertino)

"One of the most memorable, and perhaps vital to the project, was Steve saying, 'Don't think of me as the client, think of me as part of your team,'" lead architect Norman Foster said in an video presented to the Cupertino City Council.

The design was partly inspired by the main quad on Stanford University's campus, Foster said.

Stanford University (Flickr/Franco Folini)

The land under Apple Park was HP's advanced products campus before Apple tore the building down in 2013.

The land was finally fully cleared in 2014. Here's a photo from May of that year.

(YouTube/Dana Diederich (YouTube/Dana Diederich)

Then it was time to start building. This is a snapshot of the building process in February 2016.

(Youtube/Duncan Sinfield (Youtube/Duncan Sinfield)

One of the building's defining features is that it features huge panes of curved glass. According to Seele, Apple's glass supplier, Apple Park uses "something like six kilometres of glass."

A leaked photo from January provides a sneak peek into the interior:

(Apple (Apple)

The campus was designed to be light and airy — here's a rendering.

(Apple/Cupertino (Apple/Cupertino)

Even the tables inside the building have been obsessed over. Apple commissioned custom tables from Arco, a Dutch furniture maker.

Apple's table of choice is an 18-foot-long and 4-foot-wide solid white oak slab that weighs 660 pounds. It's basically a version of Arco's $2,500 Essenza table, only twice as long.

But the outside is as important as the inside. 80% of the site will be green space, and Apple is planning to plant 7,000 trees on campus.

Many of those trees, especially inside the ring, are going to be fruit trees. In this diagram, the purple dots are plum trees, the orange dots are apricot tree, the brown dots are olive trees, the red dots are persimmon trees. And of course, the yellow dots are apple trees.

(YouTube/The Daily Conversation (YouTube/The Daily Conversation)

Right now, those trees are still being planted. Landscaping is expected to extend through the end of the second quarter 2017.

Here's how Apple plants a tree:

Apple decided to plant mature trees to make the campus green quicker.

One fun fact about Apple Park: No dirt was removed from the site. For a while, there was a giant dirt pyramid on the site made out of all the earth that had been removed.

"Hard to know which is more beautiful, the building or that pile of dirt," Apple CEO Tim Cook told Vogue last year.

(YouTube/Duncan Sinfield (YouTube/Duncan Sinfield)

The building will be uncommonly environmentally-friendly. Apple says it will be the largest naturally ventilated building in the world — meaning that it won't need air conditioning or heating for most of the year.

About 4,300 concrete slabs help make up the natural ventilation system, according to Popular Science.

The slabs help the building stay cool, reports Popular Science.

Apple's campus is also positively covered with solar panels.

(Apple (Apple)

Here's a plus for fitness fanatics at Apple: There will be miles of jogging and cycling trails across the campus, and bikes on site to help employees get around. There's also a gym and fitness center that cost over $70 million to build, according to public permits.

And there's a 1,000-person auditorium for launch events and public presentations, named "Steve Jobs Theatre."

(YouTube/Matthew Roberts (YouTube/Matthew Roberts)

Employees start moving in next month. "The main building, parking structure, theatre, and fitness center are under construction," said a progress report delivered to the Cupertino City Council on March 7. "Occupancy for main building will begin in April and phased to end of 2017. Phase 2 and ancillary building expected to be completed by 2018."

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