In 1924, armed with a renewable ten-year digging concession from the Mexican government, Morley, his field director Earl H. Morris, artists Ann Axtel Morris and Jean Charlot, and several others began their first explorations. They selected an area within what appeared to be the central plaza of the site, where the capitals of some columns lay exposed. Much to their surprise they uncovered row upon row of free-standing columns — surprising since such columns hardly ever figured in Classic Maya architecture. This complex (now called the "Complex of a Thousand Columns", although the columns number fewer than one thousand), un-Maya-like in both execution and arrangement, added confirmation to earlier speculations that Chichen Itza was something of an enigma. This arrangement had much more in common with the architectural styles of civilizations in central Mexico (more than a thousand kilometres away) than that of the Classic or Pre-Classic Maya. In particular, this complex and some others which were gradually revealed appeared to have much in common with structures built at Tula, believed to be the capital of the Toltecs and which was located about 100 km north of present-day Mexico City.