[colorado tanker]

It has long been suspected that the Maya relied heavily on agriculture. In the 1970s, researchers began characterizing the remains of elaborate irrigation canals found in wetland areas. But it has not been clear how widespread these canals were or whether the use of wetlands for farming was an important part of the Maya agricultural system...

Well, yeah, somebody had to be growing a whole lotta food to support those cities.

[SunkenCiv]

The rafts on which food was grown in the boggy lake around Tenochtitlan were perhaps more impressive — they managed three crops a year, and in a two-season tropical area like the Mayans had, they should have been able to do at least that well. But yeah, a lot of labor was needed for those pyramid projects, and the next one started on top of the previous (at times), making it a decades- or century-long process.