SEATTLE — The old Battery Street Tunnel — what used to be one of the busiest arteries in Seattle — is now “filled to the grates” with concrete as one of the final pieces in the years-long project to replace the Alaskan Way Viaduct gets checked off the list.

WSDOT announced Tuesday that crews competed filling the old Highway 99 tunnel in late September.The tunnel used to connect SR-99 between Aurora Ave. North and the viaduct, but once the new waterfront tunnel opened and the viaduct began coming down, crews used the tunnel to store the recycled concrete.

They just recently filled the last 7 feet with lightweight concrete pumped through the street’s ventilation grates, says the WSDOT’s Laura Newborn.