Center Island?
This picture of an obviously abandoned building is slightly unsettling in its own right. What the person needed help identifying is actually the large, square item in the center of the room. The internet was quick to find the answer: it’s a sand table.
These were once frequently used in mission planning in the place of a table that was simply a giant map. This type of table was incredibly handy because the sand can be drawn in and then leveled again afterward for reuse.