There is a remarkable ruin at Ake, at the south, which deserves mention. Here, on the summit of a great mound, very level, and 225 feet by 50 in extent, stand 36 shafts or columns, in three parallel rows. The columns are about 15 feet high and 4 feet square. The ruins of Ake, which cover a great space, are ruder and more massive than most of the others. The island of Cozumel and the adjacent coast of Yucatan were populous when the Spaniards first went there, but the great towns then inhabited are now in ruins. [Illustration: Fig. 44.--Great Mound at Xcoch.] Water is scarce on this peninsula, and a sufficient supply is not obtained without considerable difficulty. The ancient inhabitants provided for this lack of water by constructing aguadas or artificial ponds. These, or many of them, doubtless, are as old as the oldest of the ruined cities. Intelligence, much skill in masonry, and much labor were required to construct them. They were paved with several courses of stone laid in cement, and in their bottoms wells or cavities were constructed. More than forty such wells were found in the bottom of one of these aguadas at Galal, which has been repaired and restored to use. A section of the bottom of this aguada is shown in Figure 45. In some places long subterranean passages lead down to pools of water, which are used in the dry season. One of these subterranean reservoirs, and the cavernous passage leading to it, are shown in Figure 46. The reservoir is 450 feet below the surface of the ground, and the passage leading to it is about 1400 feet long. Branching passages, not shown, lead to two or three other basins of water. [Illustration: Fig. 45.--Bottom of an Aguada.] [Illustration: Fig. 46.--Subterranean Reservoir.] The wooden lintels, which are common in Yucatan, do not appear in the other ruins, and there is a difference in the style of ornamentation between those at Palenque or Copan, for instance, and those at Uxmal, but every where the architecture is regulated by the same idea, the differences indicating nothing more than different periods and different phases of development in the history of the same people. [Illustration: Fig. 47.--Plan of the Walls at Tuloom.]