Microsoft is one step closer to getting underway with the sweeping refresh of its Redmond, Wash. headquarters campus, with construction set to start later this year.

The tech giant this week selected the team of architects, contractors and other firms that will help Microsoft build out the campus redevelopment, which includes knocking down a dozen iconic original buildings and replacing them with 18 new structures that will make room for 8,000 additional workers.

Microsoft’s Redmond campus opened in 1986, and since then it has been in a near-constant state of change. This transformation is the biggest in at least a decade for the 500-acre campus, which today totals 15 million square feet in 125 buildings on both sides of SR 520. The project also signals Microsoft’s desire to grow its workforce in the region well beyond the 47,000 people it employs in the Seattle area today.

The 18 new four- and five-story buildings will total approximately 3 million square feet sitting on 72 acres. The original two-story buildings set for demolition — which include Buildings 1 through 6 and 8 through 10, among others — total about 1.2 million square feet. (Microsoft’s missing Building 7 is the stuff of legend.) That results in a net addition of about 1.8 million square feet.

The buildings will range from 180,000 to 220,000 square feet and will be organized into four “distinct villages.” Work on the new buildings is expected to begin later this year, and Microsoft says the structures will open in 2022.

“Our new campus will be more open and modern, focused on sustainability, connectedness and accessibility. The workplaces will feature more natural light and foster the type of creativity that will lead to ongoing innovation, advance the industry and benefit our customers,” Rob Towne, regional director of Puget Sound, Global Real Estate & Facilities at Microsoft said in a statement.

Further expanding the reach of its campus, Microsoft purchased a four-building office complex in Redmond last month for $250 million. Microsoft is also in the process of redeveloping its Silicon Valley campus.

At least one relic to Microsoft’s past will remain in the new HQ project. The “Lake Bill” pond on the original campus, famous among veteran Microsofties, is staying, Smith said. Gates’ corner office in Building 4 overlooked the lake, where executives were known to take dunks to settle bets and reward sales milestones.

The original Redmond buildings — with their iconic “X-Wing” design — may stir up nostalgia among Microsoft veterans. However, they probably won’t be missed by current employees. The layout of the structures makes them notoriously difficult to navigate, and very easy to get lost inside. They date back to an era when individual offices were the tradition at Microsoft, long before the open floor plans and collaborative spaces of today.

Here is the list of companies Microsoft is working with on the redevelopment project: architects LMN, NBBJ, WRNS Studio and ZGF Architects; general contractors Skanska, Balfour Beatty, GLY and Sellen; and lead landscape architect Berger Partnership with OLIN. CBRE, JLL and OAC Services Inc. will handle project management.