The history of North Africa is typically divided into its prehistory, the classical period, the arrival and spread of Islam, the colonial era, and finally the post-independence period, in which the current nations were formed. The region has been influenced by a wide range of cultures. The development of sea travel firmly integrated North Africa into the Mediterranean world, especially during the classical period. In the 1st millennium AD, the Sahara became a major trade zone as camel caravans brought goods and people from sub-Saharan Africa. The region also has a small but strategic land connection to the Middle East, which has also played a key role in its history.