This image shows one entrance of the Bankhead Tunnel in Mobile, Alabama, which passes under the Mobile River to Blakeley Island.
The description states:
BANKHEAD TUNNEL, MOBILE, ALABAMA
Underneath the Mobile River, connecting Government Street with U. S. Highway 90, East. This 3,389 foot long underwater tunnel was completed in 1941 at a cost of $4,000,000 and is 49 feet below mean high water level of the river.
The age and size of the tunnel means that traffic is restricted to passenger cars and pickup trucks.Larger vehicles are directed to the larger and more recent George Wallace tunnel a few blocks south.
The advertisement at the left side of the image indicates this image dates from the 1950s.