An example of the improvement of architecture after Inca subjugation is shown in the curious burial-places, or _chulpas_, of the Collao, in the basin of Lake Titicaca. The earliest, as seen at Acora near the lake, closely resemble the rude cromlechs of Brittany. Next, roughly built square towers are met with, with vaults inside. Lastly, the _chulpas_ at Sillustani are well-built circular towers, about 40 feet high and 16 feet in diameter at the base, widening as they rise. A cornice runs round each tower, about three fourths of the distance from the base to the summit. The stones are admirably cut and fitted in nearly even courses, like the walls at Cuzco. The interior circular vaults, which contained the bodies, were arched with overlapping stones, and a similar dome formed the roof of the towers. [Illustration: MAP OF TITICACA, WITH WIENER’S ROUTE.] The architectural excellence reached by the Incas, their advances in the other arts and in literature, and the imperial magnificence of their court and religious worship, imply the existence of an orderly and well-regulated administrative system. An examination of their social polity will not disappoint even high expectations. The Inca, though despotic in theory, was bound by the complicated code of rules and customs which had gradually developed itself during the reigns of his ancestors. In his own extensive family, composed of Auqui[1204] and Atauchi,[1205] Palla[1206] and Ñusta,[1207] to the number of many hundreds,[1208] and in the Curacas[1209] and Apu-curacas[1210] of the conquered tribes, he had a host of able public servants to govern provinces, enter the priesthood, or command armies. [Illustration: PRIMEVAL TOMB, ACORA. [After a sketch in Squier’s _Primeval Monuments of Peru_, Salem, 1870. He considers it an example of some of the oldest of human monuments, and is inclined to believe these chulpas, or burial monuments, to have been built by the ancestors of the Peruvians of the conquest in their earliest development.—ED.]] [Illustration: RUINS AT QUELLENATA. [Reduced from a sketch in Squier’s _Primeval Monuments of Peru_, p. 7. They are situated in Bolivia, northeast of Lake Titicaca, and the cut shows a hill-fortress (pucura) and the round, flaring-top burial towers (chulpas). Cf. cut in Wiener’s _Pérou et Bolivie_, p. 538.—ED.]] The empire was marked out into four great divisions, corresponding with the four cardinal points of a compass placed at Cuzco. To the north was Chinchaysuyu, to the east Anti-suyu, to the west Cunti-suyu, and to the south Colla-suyu. [Illustration: RUINS AT ESCOMA, BOLIVIA. [After a cut in Squier’s _Primeval Monuments of Peru_, p. 9,—a square two-storied burial tower (chulpa) with hill-fortress (pucura) in the distance, situated east of Lake Titicaca. Cf. Squier’s _Peru_, p. 373.—ED.]] [Illustration: SILLUSTANI, PERU.