What was the Ancestral Puebloan’s most notable achievement?

One of the Ancestral Puebloan's most notable achievements was their advanced construction of elaborate stone and adobe cliff dwellings, such as those found at Mesa Verde and Chaco Canyon. These structures were built into the sides of cliffs and featured complex architecture and sophisticated masonry techniques. Additionally, they were skilled farmers and engineers, developing an extensive system of irrigation canals and terraced farming techniques to sustain their communities in the arid Southwest landscape.