Producing the light for the Exposition consumed 200,000 kilograms of oil an hour.[8] The facade of the Palace and the Water Castle, across from it, were lit by an additional 7,200 incandescent lamps and seventeen arc lamps.[9][6] Visitors could go inside to see the steam-powered generators which provided electricity for the buildings of the Exposition.[6][4] The Water castle, facing the Palace of Electricity, had an equally imposing appearance.