The canon of Beaver Creek in central Arizona contains one of the most interesting of these fortresses, known as Montezuma's Castle. Many small buildings nestle along the sides of the canon upon the ledges and under over-hanging rocks, but Montezuma's Castle is the most magnificent of them all, and must have given protection to a number of families. Halfway up the face of a cliff two hundred feet in height, there is a large cavern with an upward sloping floor and jagged overhanging top. Here with infinite toil the Cliff Dwellers constructed a fortress, the front of which rose forty feet from the foundation and contained five stories. This front was not made straight, but concave, to correspond to the curve of the cliff. What an effort it must have been for these people, who had nothing but their hands to work with, to quarry the stone. To carry their materials from the bottom of the canon, by means of rude ladders, up the steep and rugged wall to the foot of the cavern, and then to lay the foundation securely upon the sloping floor, must have been a still harder task. The stones were laid in mud, and in most cases were also plastered with it. Here and there little holes were left to let in light, but the rooms, with their low ceilings, would have seemed very dismal and dark to us. Beams were set in the walls to support the different floors. Smaller sticks were laid upon the beams, and then a layer of earth was placed over the top. To pass through the openings between the different rooms the inhabitants had to crawl upon their hands and knees. The places where they built their fires are indicated by the dark stains which the smoke has left upon the walls. Broken pottery and corn-cobs are scattered profusely about the building. How safe these ancient people must have felt in this retreat, where they were protected, both from the storms and from their enemies! [Illustration: FIG. 75.--MONTEZUMA'S CASTLE, BEAVER CREEK CANON, ARIZONA] Near some of the ruined dwellings in this region there are remains of buildings which are supposed to have been watch-towers. We can picture to ourselves the sentinels' alarm given to the workers in the fields at the approach of the savage Apaches, and the hasty flight of the Cliff Dwellers to the castle far up the canon wall,--the pulling up of the ladders and the retreat to the upper rooms from which they could look down in perfect safety. They must have kept water and food stored in the cave houses. As long as these supplies held out no injury need be feared from the attacking party.