What are some ancient civilizations we don't know much about?

There are many ancient civil izations that are not as well known as some of the more famous ones , such as the Egypt ians , Gree ks , and Rom ans . Some examples of less er - known ancient civil izations include : \n \n * The M ino ans , who lived on the island of Cre te in the Mediter rane an Sea from about 2 6 0 0 B CE to 1 1 0 0 B CE . They were known for their advanced art , architecture , and trade . \n * The May ans , who lived in what is now Mexico , Gu atem ala , and Bel ize from about 2 0 0 0 B CE to 1 5 0 0 CE . They were known for their complex calendar system and their s oph istic ated writing system . \n * The S umer ians , who lived in what is now Ira q from about 4 5 0 0 B CE to 1 9 0 0 B CE . They were known for their contributions to writing , mathematics , and the development of cities . \n * The Ind us Valley Civil ization , which existed in what is now Pakistan and India from about 3 3 0 0 B CE to 1 3 0 0 B CE . They were known for their advanced urban planning , se w age systems , and trade . \n * The Ol m ec s , who lived in what is now Mexico from about 1 4 0 0 B CE to 4 0 0 B CE . They were known for their col oss al stone heads and their role as the earliest known civil ization in Mes o amer ica . </s>