These are the only buildings on the west side of the camino real which are still standing; but great vestiges exist of mounds with remains of buildings upon them, and colossal stones and fragments of sculpture at their feet, which it would be impossible to present in detail. [Engraving 46: Gymnasium, or Tennis Court] Passing among these vestiges, we come out upon the camino real, and, crossing it, again enter an open field, containing the extraordinary edifice represented in the plate opposite, which, on first reaching the field of ruins, we rode in on horseback to examine. It consists of two immense parallel walls, each two hundred and seventy-four feet long, thirty feet thick, and one hundred and twenty feet apart. One hundred feet from the northern extremity, facing the open space between the walls, stands on an elevation a building thirty-five feet long, containing a single chamber, with the front fallen, and, rising among the rubbish, the remains of two columns, elaborately ornamented with sculpture; the whole interior wall being exposed to view, covered from the floor to the peak of the arch with sculptured figures in bas-relief, much worn and faded. The engraving represents the two walls, with this building in the distance. And at the other end, setting back, too, one hundred feet, and commanding the space between the walls, is another building eighty-one feet long, also ruined, but exhibiting the remains of two columns richly ornamented with sculptured figures in bas-relief. The position in which these walls and buildings stand to each other is laid down on the general plan. In the centre of the great stone walls, exactly opposite each other, and at the height of twenty feet from the ground, are two massive stone rings, four feet in diameter, and one foot one inch thick; the diameter of the hole is one foot seven inches. On the rim and border were two sculptured entwined serpents, one of which is represented in the engraving below. [Engraving 47: Sculptured Entwined Serpents] These walls, at the first glance, we considered identical in their uses and purposes with the parallel structures supporting the rings at Uxmal, of which I have already expressed the opinion that they were intended for the celebration of some public games. I have in all cases adopted the names of buildings which I found assigned to them on the spot, where any existed, and where there were none I have not attempted to give any. At Chichen all the principal buildings have names; this is called an Eglesia, or Church, of the antiguos, which was begun, but not finished, and the great open walls present not a bad idea of one of their gigantic churches before the roof is put on; but as we have already one Eglesia, and there is historical authority which, in my opinion, shows clearly the object and uses of this extraordinary structure, I shall call it, as occasion requires, the Gymnasium or Tennis-court.