To weaken the shock wave, the tunnels used to transport nitroglycerine had many breaks and branches. Most of the tunnel is underground to minimise the risk of a chain reaction. An interesting aspect related to this tunnel is its height and stairs. These two aspects are due to a design error. The two buildings that were built at the same time were connected by a tunnel. As it turned out during construction, the height of the two tunnels was not at the same level. Therefore, one of the branches was quickly built so that the tunnel could be connected.