One of my favourite maps was the one below by al-Idrisi from 1154. Idrisi was an Arab geographer from Morocco who went to Sicily to help the Norman King Roger II expand his kingdom by finding about more about the world beyond that which was already known.
Contrary to popular rumour, people knew that the world was round, but were ignorant to what lay beyond the Mediterranean region, they thought the rest of the world was all ocean.
Idrisi and Roger would quiz sailors and fishermen as they arrived into the port at Palermo each day, where had they been? What had they seen? How did they get there? How long did it take to get there?
In this map the world is upside down. Why? Well why do we put north at the top other than it's what we're used to doing?