The Common Hall (called the Downstairs Corridor in the PAL versions) is a room in Gloomy Manor in the game Luigi's Mansion: Dark Moon. It is one of the longest rooms in the game and it is accessed from the Foyer and leads to the Lab, Secret Pocket, and the Parlor.
During A-4: Visual Tricks Luigi has to go through the Common Hall once more to get into the Lab to get the Dark-Light Device. However, the door to the Lab disappears due to the Spirit Balls making it invisible forcing him to find another way around. After getting the Dark-Light Device and revealing a Key in a picture frame, Luigi has access to the Patio to continue his mission.
During A-5: Sticky Situation, Luigi has to visit the Common Hall once more this time to get rid of the spider webs that overflow the hall.