. ▁This ▁structure ▁had ▁square ▁columns ▁and ▁two ▁ident ically ▁s ized ▁ch amb ers , ▁separated ▁by ▁a ▁space ▁with ▁two ▁columns . ▁The ▁northern ▁chamber ▁had ▁an ▁entrance ▁on ▁the ▁east ▁side , ▁with ▁a ▁possible ▁additional ▁entrance ▁on ▁the ▁south ▁side . ▁ ▁Str ucture ▁B 1 - 2 ▁Str ucture ▁B 1 - 2 ▁dates ▁to ▁the ▁Late ▁Classic . ▁It ▁is ▁located ▁to ▁the ▁south west ▁of ▁the ▁main ▁py ram id ▁B 1 - 1 . ▁It ▁is ▁a ▁west - f acing ▁py ram id ▁with ▁three ▁stepped ▁levels ▁standing ▁upon ▁a ▁low ▁bas al ▁platform . ▁It ▁was ▁built ▁using ▁the ▁tal ud - tab ler o ▁style ▁of ▁architecture ; ▁the ▁py ram id ▁measures ▁ ▁and ▁stands ▁approximately ▁ ▁tall . ▁In ▁October ▁ 2 0 0 4 ▁the ▁south ▁side ▁of ▁the ▁py ram id ▁col lapsed ; ▁this ▁is ▁believed ▁to ▁have ▁been ▁caused ▁by ▁a ▁combination ▁of ▁damage ▁caused ▁by ▁the ▁roots ▁of ▁nearby ▁trees ▁and ▁water ▁damage . ▁The ▁rest oration ▁of ▁the ▁py ram id ▁with ▁c ement ▁in ▁the ▁ 1 9 5 0 s ▁had ▁converted ▁the ▁structure ▁into ▁a ▁water ▁trap , ▁while ▁ced ar ▁roots ▁had ▁pen etr ated ▁the ▁building ▁to ▁a ▁height ▁of ▁ ▁causing ▁significant ▁crack ing . ▁ ▁Str ucture ▁B 1 - 2 ▁under w ent ▁four ▁phases ▁of ▁construction . ▁The ▁earliest ▁phase ▁had ▁a ▁total ▁height ▁of ▁; ▁the ▁lowest ▁level ▁measured ▁ ▁high ▁while ▁the ▁middle