In the woods to the south of the Castillo are a group of large and well-preserved ruins. First the "Red House," a literal translation of the Indian name _Chichanchob_, in allusion to the extensive colouring of the inner walls. The building, which is 43 feet long and 23 deep and has a richly ornamented cornice, stands on a low mound 62 feet long and 50 odd wide, approached by a stairway 20 feet wide. It has three doors admitting to a room running the full length of the building; and out of this again there are three doors to three inner rooms. Along the top of the wall of the front room runs a tablet covered with two lines of hieroglyphics. They are much worn, and we found it impossible to get a satisfactory mould of them. The paints on the walls are still vivid, but no pattern is traceable; the only striking feature being that "red hand," which we found in far better preservation at a city we discovered some months later in the island of Cozumel, and of which we shall write later. To the south-east of the Chichanchob is a most puzzling building, unique as far as Yucatan is concerned. The Caracol, or "Winding Staircase," stands on two rectangular stone-faced terraces reached by steps. The lower terrace measures 220 feet north to south, 150 feet east to west, and is 20 feet high. The masonry is very rough, and may have been plastered. At one end are the remains of four small pillars, and around the building we found at intervals carved heads hollowed in the crowns to serve as incense-burners. The stairs are on the west side, and are 45 feet wide; the broken remains we found suggested there had been serpent balustrades. The second or upper terrace is 60 feet east to west, 80 north to south, and 12 feet high; the steps being a continuation of the lower flight. The building is a large squat turret of about 40 feet diameter and about 25 in height. Upon this turret a smaller one, now largely fallen, stood. The main turret consists of two concentric walls, enclosing two annular rooms and a circular core or pillar. The walls are some 2 feet thick. There are four doorways facing the cardinal points of the compass in the outer, and four facing the sub-cardinal points in the inner, wall. The core is about 7 feet thick at the floor-level and 8 feet at ceiling. The roof of each of these annular rooms ends in a very pointed arch. Facing the north-east door is a small opening in the core about 4 feet from the floor and measuring about 28 by 24 inches. J. L. Stephens in 1842 abandoned the attempt to explore this, but we were luckier. By a total disregard of our clothes and of the probability that the passage sheltered at least one rattlesnake, we squirmed through and came out at the side of the topmost turret some 10 feet from the top. Undoubtedly this was once a stairway, for we could feel (it was too dark to see) the broken edges of the steps. It is reasonable to surmise that this unique winding-stair building was in the