The current metallic staircase, suspended by steel tie-beams, designed by the architect Andrea Bruno and completed in 1984, can be found in the same space once occupied by part of the 18th century staircase. From Juvarra's original design only the foundation and the first flight of stairs outside the castle were built. Some writing can still be seen on the walls which relates to the planning of the staircase support system designed at the end of 18th century by Carlo Randoni but left incomplete.