Sea in culture of barbarian invaders and knowledge of geography took a backward step. In the seventh century, Isidore of Seville produced a "wheel map" in which Asia, Africa and Europe were arranged like segments in an orange, separated by the "Mare Mediterranean", "Nilus" and "Tanais" and surrounded by "Oceanus". It was not until the fifteenth century that Ptolemy's maps were used again and Henry the Navigator of Portugal initiated ocean exploration and maritime research. Encouraged by him, Portuguese navigators explored, mapped and charted the west coast of Africa and the Eastern Atlantic and this knowledge prepared the way for the great voyages
Internet in Africa Asia has 800,000 Mbit/s and Europe over 3,000,000 Mbit/s. The total bandwidth available to Africa was less than that available to Norway alone (49,000 Mbit/s). As a consequence of the scarce overall bandwidth provided by cable connections, a large section of Internet traffic in Africa goes through expensive satellite links. In general, thus, the cost of Internet access (and even more so broadband access) is unaffordable by most of the population. According to the Kenyan ISPs association, high costs are also a consequence of the subjection of African ISPs to European ISPs and the lack of a clear international regulation