Complex sentence: The ritual structure was built on a Predynastic cemetery and excavations there, as well as the work of later brick robbers, have seriously undermined the walls and led to the near collapse of the structure.
Split into simpler sentences: The ritual structure was built on a Predynastic cemetery. The excavations there, as well as the work of later brick robbers, have seriously undermined the walls and led to the near collapse of the structure.