The mysterious lower level at Vallco Shopping Mall (previously, Cupertino Square, previously Vallco Fashion Park) is,
After discovering the walls around the portal to the lower level removed, I raced downstairs and found an open door. These exclusive photos show the lower level under construction. This view is from the cinema towards Macy's.
Vallco mall directories have long stated "under construction" for the lower level, which made its debut the 80s, then disappeared in the 00s.
Remark from a curious bystander: "what are they going to fill it with?" Vallco, considered a "dead mall," is suffering from low occupancy. Good question.