Complex sentence: In 1999 the upper film with the dome and the pendulum was replaced by the lower film, as the bottom screen was removed and an iron floor was placed along with blue light strips and a replica of a volcanic crater.
Split into simpler sentences: In 1999 the upper film with the dome and the pendulum was replaced by the lower film as the bottom screen was removed. Instead an iron floor was placed along with blue light strips and a replica of a volcanic crater.