Starcourt Mall is the first mall to open up in Hawkins and much of season 3 involves it. While many of the main
characters go to the mall for fun and for their jobs at first, they later find out that there's much more going on.
The real reason starcourt mall was built was to be used as a secret Russian base.

The Russians chose to put the base in Hawkins because it the perfect place to open the portal back up to the upside
down. After working away for a while, they finally open the portal back up using tons of energy. With the help of
the Russians, the shadow monster was able to make its way back into Hawkins to continue tormenting the main
characters.

Pictured to the right is the very high energy device that was able to open the portal back up to the upside down.