The pillars, some up to 18 feet (5.5 m) tall and weighing 16 tons, were cleanly cut from limestone quarries up to a quarter mile away, then moved to the site, without wheels or domesticated animals. The generally accepted theory about the development of civilization used to be that people developed agriculture, allowing them to settle in larger villages, which led to specialization and religion, but this site seems to have been built before the development of agriculture and without permanent settlements. It's one of many findings raising questions about the standard theory.