The Olmecs were the first inhabitants of the Americas to construct monumental architecture and to settle in towns and cities . They were also the first people in the Americas to develop a sophisticated style of stone sculpture . In the first decade of the 21st century evidence emerged of Olmec writing , with the earliest examples of Olmec hieroglyphs dating to around 650 BC . Examples of script have been found on roller stamps and stone artefacts ; the texts are short and have been partially deciphered based on their similarity to other Mesoamerican scripts . The evidence of complex society developing in the Olmec heartland has led to the Olmecs being regarded as the " Mother Culture " of Mesoamerica , although this concept remains controversial .