The North Acropolis , together with the Great Plaza immediately to the south , is one of the most studied architectural groups in the Maya area ; the Tikal Project excavated a massive trench across the complex , thoroughly investigating its construction history . It is a complex group with construction beginning in the Preclassic Period , around 350 BC . It developed into a funerary complex for the ruling dynasty of the Classic Period , with each additional royal burial adding new temples on top of the older structures . After AD 400 a row of tall pyramids was added to the earlier Northern Platform , which measured 100 by 80 metres ( 330 by 260 ft ) , gradually hiding it from view . Eight temple pyramids were built in the 6th century AD , each of them had an elaborate roofcomb and a stairway flanked by masks of the gods . By the 9th century AD , 43 stelae and 30 altars had been erected in the North Acropolis ; 18 of these monuments were carved with hieroglyphic texts and royal portraits . The North Acropolis continued to receive burials into the Postclassic Period .