Location for Underground Passageways

Anyone have an idea where the location was for the underground passageways?

The meeting hall seems to be a set, but the passageways seem an underground storm drain or some kind of warehouse. In the scene where Nada and Frank first drop down, a huge round opening on the left looks like an overflow intake.

I tried to read the lettering on the ground, as it seemed natural, not like the dual-language signs on the wall. It said something like "All carts must stop."

There is one scene that appears to have forced perspective matte, though.