1.   State and federal laws require that explosives be stored in padlocked metal magazines that are resistant to weather erosion, fire, bullets and theft.

2.   The monuments are built of limestone, which is crumbling from weather erosion and air pollution.

3.   The pyramids and the adjacent Sphinx are built of limestone, which is crumbling from weather erosion and air pollution.

4.   They and the adjacent Sphinx are built of limestone, which is crumbling from weather erosion and pollution from surrounding urban sprawl.

5.   They and the adjacent Sphinx are built of limestone, which is crumbling from weather erosion and pollution resulting from surrounding urban sprawl.