Complex sentence: The rest was acquired in 1880 by the Imperial Museum of Berlin (it was on display for a time at the Pergamon Museum), in whose hands it remained until 1945, when it mysteriously disappeared from a protective bunker beneath the Berlin Zoo.
Split into simpler sentences: The rest was acquired in 1880 by the Imperial Museum of Berlin. There it remained until 1945, when it mysteriously disappeared from a protective bunker beneath the Berlin Zoo.