Facebook is planning on constructing a large research facility in Redmond off Willows Road, which could house part of its virtual reality program.

The project is detailed in pre-application documents filed with the city of Redmond dating back to June. The project will be located across the street from Willows Run Golf Complex at 10201 and 10301 Willows Road, on more than 15 acres. The five-story development is being called Building X and would house research labs, meeting spaces and kitchens.

According to the documents, the building will have nearly 1,400 parking spaces below the research facility. In total, the project will include 678,000 square feet of space and several of the roofs will be planted with large trees. These rooftop forests will cover nearly 2.5 acres, similar to Facebook’s Menlo Park complex in California. The remaining rooftops will be fitted with solar panels.

The project is being designed by the California-based developer Gehry Partners. Facebook did not respond to a request for comment and a spokesperson for the city of Redmond said they did not have additional information on the project.

In the documents, Building X is planned to be constructed in a way that makes it hard to see, if not invisible, from the road and golf course. It will be set back from the road in addition to having trees planted on many of its roofs. Two existing buildings onsite will be demolished and the Puget Sound Business Journal reported construction could begin as early as next spring.

Facebook is hiring, looking to fill more than 170 positions in Redmond, including nearly 70 for Facebook Reality Labs and 38 for Oculus, its virtual reality program. Facebook already has space in Redmond near the Microsoft campus and it is unclear how many of these positions would be placed at Building X. It also remains unknown exactly what will be researched at the Building X facility, but plans call for several of its labs to have high, glass ceilings to let in natural light.