The limestone used for construction was local and quarried on-site. The depressions formed by the extraction of stone for building were plastered to waterproof them and were used as reservoirs, together with some waterproofed natural depressions. The main plazas were surfaced with stucco and laid at a gradient that channelled rainfall into a system of canals that fed the reservoirs.
The residential area of Tikal covers an estimated 60 square kilometres (23 sq mi), much of which has not yet been cleared, mapped, or excavated. A huge set of earthworks has been discovered ringing Tikal with a 6-metre (20 ft) wide trench behind a rampart. The 16 square kilometres (6.2 sq mi) area around the site core has been intensively mapped; it may have enclosed an area of some 125 square kilometres (48 sq mi) (see below). Population estimates place the demographic size of the site between 100,000 and 200,000. Recently, a project exploring the defensive earthworks has shown that the scale of the earthworks is highly variable and that in many places it is inconsequential as a defensive feature. In addition, some parts of the earthwork were integrated into a canal system. The earthwork of Tikal varies significantly in coverage from what was originally proposed and it is much more complex and multifaceted than originally thought.
very primitive in 1988
photographing with his Mayan language chart