As a first step toward fulfilling its vision of constructing a massive underground tunnel transit system in Los Angeles, Elon Musk’s Boring Company has been building a proof-of-concept tunnel under its headquarters in Hawthorne, California.

On Sunday, Musk tweeted that the test tunnel will be completed Dec. 10 and the company will offer free rides the following day to anyone interested in getting a glimpse of what could be the future of mass transit for the world’s major cities.

The first tunnel is almost done
— Elon Musk (@elonmusk) October 22, 2018

Musk, who's known for not always meeting promised deadlines, was asked by a Twitter user if the Dec. 10 goal was in "real time" or "Elon time", to which the CEO replied: "I think real."

The test tunnel in Hawthorne is two miles long and has a top speed of about 150 mph, according to The Boring Company website.

"Loop is a high-speed underground public transportation system in which passengers are transported on autonomous electric skates traveling at 125-150 miles per hour," the company says on its website. "Electric skates will carry between eight and 16 passengers (mass transit), or a single passenger vehicle."

In September, the Hawthorne City Council granted approval for the company to build a prototype of an elevator system that would connect a residential garage to the underground tunnel.

Please tell me you're going to make it look cool inside the tunnels! 🙏❤️ pic.twitter.com/V2awNU6sxh
— Pkmn Master Holly (@PkmnMasterHolly) October 22, 2018