original: Notably absent from the city are fortifications and military structures.
simplifications: Notably gone from the city are fortifications and military structures. The city has no walls or military buildings. Absent from the city are forts and military buildings. Fortifications and military structures aren't in the city. The city does not have any defensive structures or military structures. There are no fortifications and military structures in the city. Fortifications and military structures are notably absent from the city. The city does not have fortifications or military structures. Fortifications and military structures are absent from the city. Notably absent from the city are military structures and defenses.