this archeological site was the town which was abandoned in favor of the new settlement on the valley floor after the spanish conquest of the aztec empire. it is located on tetepetl hill, just north and west of the modern town's main square. it was the largest fortified city in the valley of toluca in pre-hispanic times. it was excavated in the 1970s by the instituto mexiquense de cultura, who continues to maintain the site as well as the roman piña chan archeological museum located at the base of tetepetl hill. this site is one of the major tourist draws for the state of mexico after teotihuacan, valle de bravo and chalma. the obelisk that marks the entrance to the reconstructed site was built in the 1930s and is in honor of ignacio lopez rayon. it is built to emulate the style of the pyramid of conjuto a. the archeological zone of teotenagno receives about 4,000 visitors annually.