Stephens explored chultunes [underground cisterns] at several sites. He writes: "The opening was a circular hole, eighteen inches in diameter. The throat consisted of five layers of stones...about a yard deep, and the Indians lowered me down, without any obstruction, to the bottom. It did not..require much time to explore this vault. It was clear of rubbish, perfect and entire in all its parts, without any symptoms of decay, and to all appearances, after the lapse of unknown years, fit for the uses to which it was originally applied. Like the one on the terrace, it was dome-shaped, and the sides fell in a little toward the bottom, like a well-made haystack. The height was ten feet and six inches directly under the mouth, and it was seventeen feet six inches in diameter. The walls and ceiling were plastered, still in a good state of preservation, and the floor was of hard mortar."
(Stephens, vol. 1, pp. 133-134)