▁something ▁else ▁in ▁the ▁other . ▁What ▁he ▁is ▁holding ▁has ▁been ▁interpreted ▁as ▁a ▁rit ual ▁kn ife ▁or ▁a ▁cer emon ial ▁can e ▁in ▁one ▁hand ▁and ▁a ▁human ▁head ▁or ▁a ▁shield ▁in ▁the ▁other ▁hand . ▁ ▁The ▁" Second ▁Building " ▁and ▁the ▁" Th ird ▁Building " ▁were ▁constructed ▁much ▁later , ▁on ▁top ▁of ▁the ▁First ▁Building ▁and ▁to ▁cover ▁a ▁much ▁larger ▁area . ▁They ▁date ▁from ▁approximately ▁ 1 6 0 0 ▁BC ▁to ▁ 1 2 0 0 ▁BC . ▁The ▁Third ▁Building ▁is ▁the ▁most ▁monument al ▁with ▁both ▁public ▁squares ▁and ▁private ▁areas ▁and ▁with ▁many ▁walls ▁decor ated ▁with ▁relief ▁car v ings . ▁After ▁the ▁three ▁buildings ▁on ▁the ▁site ▁were ▁abandoned , ▁they ▁were ▁used ▁as ▁a ▁gra vey ard ▁up ▁until ▁the ▁fif teenth ▁century ▁AD . ▁The ▁construction ▁of ▁the ▁Second ▁and ▁Third ▁Build ings ▁was ▁orient ed ▁toward ▁Cer ro ▁Se chin , ▁ ▁distant ▁on ▁the ▁other ▁side ▁of ▁the ▁Se chin ▁Valley . ▁That ▁indicates ▁co operation ▁( or ▁sub ord ination ) ▁among ▁the ▁build ers ▁of ▁the ▁two ▁sites . ▁ ▁The ▁husband ▁and ▁wife ▁arch ae ological ▁team ▁of ▁the ▁Poz or sk is ▁have ▁spec ulated ▁that ▁Se chin ▁B ajo ▁and ▁other ▁Cas ma / Se chin ▁cities ▁and ▁cer emon ial ▁cent ers ▁were ▁conquer ed ▁about ▁ 1 0 0 0 ▁BC ▁by ▁inv aders ▁from ▁the ▁high lands . ▁The ▁pur port ed ▁inv