1.   A NATO-led force, called SFOR, was installed to keep the peace.

2.   If the wires are aluminum, and are loose, a special connection can be installed to keep them tight.

3.   In some buildings, remote-control cameras can be installed to keep building personnel in the lobby informed of rooftop activities and conditions.

4.   Iron gates, metal detectors, video cameras and lights have been installed to keep the groups separated.

5.   To protect the caverns, airlocks have been installed to keep dry air from blowing in and drying out the inside.

6.   Why, sometimes even a high fence was installed to keep the morbidly curious from viewing that final plunge.

7.   Now, storms and rot have left holes in the roof, and a system of heavy timbers and jacks has been installed to keep it in place.

8.   Its walls are full of cracks, and pillars have been installed to keep the edifice from collapsing.