What was the Mayan’s most remarkable achievement? Although building cities, developing the calendar and their trade network was remarkable, the most remarkable thing was the number system. It’s remarkableness depended on effort, genius, scale, and significance. The reason the Mayan number system was so remarkable and genius was because they only had 3 symbols. One of the symbols was a dot which stood for 1, the other a line which stood for 5, and the last was a shell which stood for 0. They used a shell to represent 0 because shells were special to the Mayans. The scale was very large, it affected everyone. It still affects people today, because they had a ones, tens, and hundreds place and now we do. They used the number system for keeping