Expedia Group has started the countdown clock to the opening of its shiny new waterfront headquarters campus in Seattle.

The first of 4,500 employees will descend on the 40-acre campus in 90 days, beginning a major cross-regional move by one of the Seattle area’s best-known companies. Expedia employees will move in waves starting in early October, and they will find more than 500,000 square feet of renovated office space that used to be labs for biotech giant Amgen.

Expedia has invested a ton of money in the project — it bought the site in 2015 for $229 million, and the campus refresh will cost upwards of $900 million. Expedia is working on two more buildings that will open next year, and the company has the approval to continue building out the campus even further over the next decade. It could eventually house more than 8,000 workers.

For Expedia employees, the new HQ is not only in a new city, 12 miles west of its existing Bellevue headquarters across Lake Washington. It’s a totally different environment — Expedia is trading out a downtown high-rise in Bellevue for a sprawling campus with plenty of green space and stunning waterfront views in the Interbay neighborhood of Seattle.

The new campus will feature “biophilic design,” which involves connecting people and nature to increase physical and mental well-being through views of the water, mountains and open office spaces with plenty of natural light. Expedia plans several acres of outdoor spaces including playing fields, meeting spaces and an amphitheater that will have WiFi and enhanced mobile data.

In the middle of the campus is a centerpiece mixed-use building akin to the Amazon Spheres called the Prow. A prow is the forward-most part of a ship’s bow that cuts through the water.