interior of a large, circular tunnel under construction

interior of a large, circular tunnel under construction. Sunlight streams in from the opening at the top, illuminating the construction site. A set of stairs are partially constructed, supported by scaffolding. Blue tarps are placed on many of the steps. Construction workers wearing orange clothing are visible at the top of the stairs. Scaffolding materials and other equipment are scattered around the base of the stairs. The walls of the tunnel appear to be rough concrete.