Elon Musk gave his Twitter followers a first look at The Boring Company’s new tunnel, set to open next month in the Los Angeles area.

In a sped-up 34-second video, Musk showed what it will be like to travel inside the two-mile tunnel, which he called “disturbingly long.”

Walked full length of Boring Co tunnel under LA tonight. Disturbingly long. On track for opening party Dec 10. Will be very one-dimensional. — Elon Musk (@elonmusk) November 3, 2018

The test tunnel is set to open Dec. 10, with free rides for the public the following day, according to tweets from Musk. He added that the top speed in the tunnel is 155 mph.

The tunnel, which is being used for research and development, is an important first step for The Boring Company in its quest to create an underground transportation network.

The goal is to alleviate city congestion by digging a network of tunnels, where cars could travel on skates carrying them well above highway speeds. However, there are still significant hurdles before Musk’s plans to build two tunnels for public use in the Los Angeles area actually come to fruition.

One proposed tunnel is in Los Angeles’ congested Westside. The Los Angeles County Metropolitan Transportation Authority said in May it would coordinate with The Boring Company on “proof of concept” for the proposed tunnel, which would span nearly three miles.

Musk announced plans for a separate 3.6-mile tunnel in August that would carry people between Dodger stadium and a nearby metro stop in under four minutes. As many as 16 people would travel on large skates, moving as fast as 150 mph, according to the plans posted online.

Both plans have generated plenty of headlines, excitement, and criticism, but they’re likely not going to happen in the immediate future. The tunnel plans are expected to face significant reviews, ensuring safety, environmental, and construction concerns are addressed, long before anyone will get to zoom around Los Angeles the way Musk imagined.