Mesoamerica is a historical region and cultural area in North America. It extends from approximately central Mexico through Belize, Guatemala, El Salvador, Honduras, Nicaragua, and northern Costa Rica. The first civilization in central and north America develops in about 1200 BC in the coastal regions of the southern part of the Gulf of Mexico. Known as the Olmec civilization, its early site is at San Lorenzo. In Mesoamerica the Maya civilization made the greatest progress in science and technology. Among its innovations were the position-value number system with zero, the development of the most accurate known calendar, the invention of rubber and the corbelled arch.