Complex sentence: The clock has a case that blends Romanesque and Byzantine styles and is crowned by a multi-tiered Celestial City with 68 automatons that animate at the striking of each hour to to enact the Last Judgement.
Split into simpler sentences: The clock has a case that blends Romanesque and Byzantine styles. It is crowned by a Celestial City represented by 68 automatons that animate at the striking of each hour to to enact a depiction of the Last Judgement.