The Mayan site of Parque Arqueológico Kaminaljuyú occupied the valley where Guatemala City  now stands. It was first settled sometime around 400 B.C. and grew to house an abundance of flat-topped pyramids (with the remains of nobility buried underneath) by A.D. 100.
The first inhabitants of the site appear to have been some early cultures (Las Charcas, Miraflores, and Esperanza, dating from 1500 B.C. to A.D. 150), which developed a foundation for the later development of the Classic Mayan culture here. These early cultures are characterized by the development of agriculture, weaving, pottery making, and ritual burial of the dead in temple mounds and shrines.
Central to the city’s rapid population growth was the development of a series of irrigation canals drawing upon the ancient lake of Miraflores. Eventually the lake began to dry out, leading to widespread migration out of the city.
Its Chol-speaking inhabitants are thought to have moved on to El Salvador and maybe even Copán , Honduras. The site’s historical record fades out (momentarily) sometime between the 2nd and 3rd centuries A.D.
With the rise of Central Mexico’s Teotihuacán in the 5th century, the Guatemalan highlands received a large influx of invaders from the north. Here the invaders established their regional capital, constructing new temples and structures, and flourished with the control of trade networks around highly prized obsidian and jade.
It is thought that, along with its powerful neighbor to the north, Kaminaljuyú exercised considerable influence over the Petén lowland sites, in particular Tikal . One of Tikal’s rulers, Curl Nose, may actually have come from here in A.D. 387.
The site was first excavated in 1925 and yielded potsherds and clay figurines from the early cultures. Its larger extent and importance were discovered in 1935 when a local football team uncovered a buried structure after cutting away the edges of two inconspicuous mounds to lengthen their practice field.
Today the site is really no more than a series of mounds. Though the site is in Zona 7 proper, the best place to see it is actually near the Museo Miraflores  in adjacent Zona 11, where you can tour the excellent museum and see some temple mounds.