Video above is from The Virginia Department of Transportation.

PORTSMOUTH, Va. (WAVY) — The Hampton Roads Bridge-Tunnel Expansion project is in a league of its own when it comes to road construction projects.

The latest update posted on social media by the Virginia Department of Transportation, or VDOT, shows a quick tour of the progress inside the latest tunnel.

On April 17, the headwall came down revealing Mary, the tunnel boring machine, tirelessly powering through.

In June, Mary finished her last ring for one of the eastbound tunnels. VDOT said that soon Mary will begin on the twin tunnel.

“The tunnels run east and west,” a spokesperson with VDOT said, back in June. “Both new tunnels will serve eastbound traffic. So we will have two new eastbound tunnels and the two current tunnels will be all westbound traffic.”

It is the largest highway construction project in Virginia’s history, according to the project’s website. The latest undertaking is expected to widen the current four-lane segments along nearly 10 miles of the I-64 corridor in Norfolk and Hampton, with new twin tunnels across the harbor.

The photo below from the HRBT depicts the map of the project.

The project’s total budget is more than $3.9 billion.