A long underground corridor led from the measurement blockhouse to a room in the concrete foundation by the flame pit, and multiple rows of measurement cables covered the walls of the tunnel. A different gradually rising tunnel led from the long flame pit room to the exterior of the arena near the pumphouse (German: Pumpenhaus). Near the pumphouse were high wooden towers to cool the water, and 25 feet (7.6 m) high tanks for the recooling water were integrated into the ellipse wall.[1][2]