The main space, almost 240 metres long, was constructed with an iron, steel and glass barrel-vaulted roof, making it the last of the large transparent structures inspired by London’s Crystal Palace that were necessary for large gatherings of people before the age of electricity. The main space was originally connected to the other parts of the palace along an east-west axis by a grand staircase in a style combining Classical and Art Nouveau, but the interior layout has since been somewhat modified.