Musk´s idea of drilling underground tunnels to ease traffic in highly congested cities like Los Angeles and Las Vegas, initially began as a joke in 2016. Now it has become a full-fledged business called The Boring Company with several nascent projects in the major cities, including Chicago and Baltimore.

Musk tweeted Friday night that Boring Company is completing its first commercial tunnel in Las Vegas, from the Las Vegas Convention Center to the Strip, before working on other projects.

Musk and The Boring Company have been working to revolutionize the way people travel with the Loop and Hyperloop high-speed transport systems. The underground tunnels will transport people in cars or passenger “capsules,” which will allow travelers to avoid traffic and move through cities faster.

When completed, the Las Vegas project will consist of two tunnels, each approximately one mile long. Passengers will be transported through autonomous vehicles at a speed of up to 249 km/h (155 miles per hour), the company says.