Microsoft staff are beginning their building farewells as the company prepares for a major overhaul of its Redmond, Wash. headquarters campus starting later this year.

Dave Heller, a senior product marketing manager for Microsoft 365, tweeted an ode to Building 1 last week, indicating that demolition was coming soon.

Goodbye building 1 😢 May the demolition guys get lost trying to find second floor conference rooms for old times sake. pic.twitter.com/PH3a9hBEIw — Dave (@DaveEHeller) September 21, 2018

A Microsoft spokesperson told GeekWire that demolition of the old buildings is not imminent. On a visit to the campus Monday, GeekWire spotted people working in Buildings 1 through 4.

Microsoft plans to knock down a dozen iconic original buildings and replace them with 18 new structures that will make room for 8,000 additional workers. In July, the company said work would begin later this year, and the new buildings would be ready by 2022.

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 more than 125 buildings on both sides of SR 520. The project also signals Microsoft’s desire to increase its workforce in the region well beyond the nearly 49,000 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. That results in a net addition of about 1.8 million square feet.

Microsoft’s missing Building 7 is the stuff of legend.

At least one nod 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. 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 it’s 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.

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.