Boeing connected the upper level of the 747 with the main cabin by a graceful spiral staircase that was based on a similar design from the Boeing 377 Stratocruiser.
Credit: National Air and Space Museum Archives
Boeing connected the upper level of the 747 with the main cabin by a graceful spiral staircase that was based on a similar design from the Boeing 377 Stratocruiser.
Credit: National Air and Space Museum Archives