world. This is supported by the fact that Lake Kopais, the largest lake in southern Greece, had been drained by a system of dams and canals (one of the most astonishing achievements of prehistoric engineering) at about the same time as the erection of Gla, producing a large fertile plain. The drainage system collapsed from destruction or neglect at or after the end of Mycenaean Civilisation; in Classical Antiquity, the lake existed again. It was drained a second time in the 19th century. The system comprised two large canals that met about 1 km north of Gla. These canals combined covered over 50 km in length, and collected water from the Boeotian Cephissus and Melas rivers and redistributed them into areas where the water flowed out to sea easily. Interior structures Palace The most striking interior feature is a large L-shaped building, often described as a "palace". It is in the north of the site, which is subdivided by several internal walls in this area. The "palace" is located on an artificial terrace and consists of three wings. Each of the wings contains mostly very small rooms, arranged in groups of six and accessed by corridors. At the two ends of the L, there are similar arrangements of rooms resembling the megaron complexes known from Tiryns, Mycenae Dimini and Pylos. Nevertheless, the lack of several typical features of other Mycenaean palaces, namely of a "throne room", a (circular) hearth and a "bathroom" casts some doubt on the designation of the structure as a palace. Agora Two further Mycenaean architectural complexes were found further south, in the area of the so-called "agora", which is separated from the "palace area" by a wall. The two complexes are parallel to each other (north-south orientation) and have similar plans. In each, a long corridor links buildings in the north and south of the complex. They are subdivided into small rooms. There is no scholarly consensus on their function. Suggestions include use as barracks, storage spaces/distribution centres, or workshops. The storage theory is supported by the discovery of large amounts of carbonised grain (probably burnt during the destruction of the site) in one of the buildings. Tiles An interesting feature of the buildings at Gla is the discovery of fired pan and cover tiles, suggesting that some Mycenaean buildings already featured pitched, tiled roofs similar to those known from Classical antiquity. There is some evidence