Staircase introduction: According to common sense, Building No. 1 only has two floors, and there is no need for a spiral staircase at all. The establishment of the spiral staircase was based on the fact that Lin Biao was old and in poor health at the time. The spiral staircase can be installed after a step. , set up another platform, let Lin Biao climb a step, rest on the platform, and then climb the step again. This spiral staircase is made of high-quality natural marble, which shows its high cost.