An image from a video posted on Instagram by Boring Co. shows the company’s Hawthorne tunnel with a narrow railway track. (Boring Co.) Elon Musk announced Sunday that the first tunnel of a proposed underground transportation network across Los Angeles County would open Dec. 10. “The first tunnel is almost done,” Musk tweeted to his 23.1 million followers shortly after 5 p.m. Musk’s Boring Co. is building the tunnel beneath the city of Hawthorne, part of his grand vision for a transportation network that whisks commuters across the county. Last year, Hawthorne officials approved the Boring Co.’s request to tunnel west from Space X headquarters. At the time, they said the tunnel had extended 500 feet. The company has said its technology could move vehicles, as well as pods carrying passengers and bicyclists, through tunnels at speeds of up to 130 mph. A video simulation released by the company last year shows a driver steering a vehicle onto a car-sized platform on the street, parallel to the curb. The platform, called a skate, sinks like an elevator, then carries the car through the tunnel. In subsequent tweets Musk said there would be an opening event on the night of Dec. 10 and free rides for the public the next day. When asked if the date represented real time or “Elon time,” the entrepreneur wrote, “I think real.” In April, the Los Angeles City Council’s public works committee unanimously approved an environmental review exemption for a Boring Co. tunnel that could run 2.7 miles under West Los Angeles. The proposed route would be parallel to Sepulveda Boulevard, starting at Pico Boulevard and running down to Washington Boulevard in Culver City. The tunnel entrance would be located in what is currently a lumber yard and welding area, the company has said. However, just a few weeks later, two neighborhood groups sued the city over its proposal to fast-track the project by exempting it from environmental review. In Culver City, where the Sepulveda tunnel could end, officials are contemplating their own court challenge. And debate continues over the effect Musk’s transportation initiative could have on surface traffic, economic equity and the environment. In August, Musk announced a proposal to build a 3.6-mile tunnel that would carry fans between Dodger Stadium and a nearby Metro subway station. But this plan is expected to face a thicket of requirements and approvals from regulators in California and Washington before construction could even begin. 10:30 a.m., Oct. 22: This article was updated with more background. 8:00 p.m.: This article was updated with background on the tunnel project. This article was originally published at 6:55 p.m.