Complex sentence: Babylon 5 was designed as the last best hope for peace, it was the last of 5 stations to be built with its predecessors either being destroyed or in the case of Babylon 4, vanishing.
Split into simpler sentences: Babylon 5 was designed as the last best hope for peace. It was the last of 5 stations to be built with its predecessors either being destroyed, or in the case of Babylon 4, vanishing.