Latin America

to create such massive buildings are huge. There had to be a specialization of skills, designers, and coordinators. Also, a large labor source which suggests a bottom rung class of workers or enslavement for the tedious labor. Skilled artisans would have done the design and artistic carvings.

There also had to be a class of mathematicians and scientists to do the calculations, measurement, and celestial alignments. In comparison with European and Middle Eastern/north African civilizations, it's like a combination of Egyptian and Roman talent rolled into one.

There also must have been a strong, unifying cultural identification and ideology that supported the civilization's development and governance for centuries.