Here's an interesting tale of explorational adventure in the classical world according to General History of Africa II, Ancient Civilizations of Africa, vol 2 (1981), p.448:
"According to Herodotus (fifth century), the Egyptian King Necho (c. -610 to -594) sent Phoenician mariners to sail down the Red Sea and thence to circumnavigate Africa. They are said to have taken two years on the journey, having twice halted to sow and reap a crop of wheat. Herodotus believed that the voyage had been successful and it is not impossible, but it had no repercussions at the time; if it took place, the vast size of the continent thus revealed must have removed any ideas of a route from the Red Sea to the Mediterranean. The Carthaginians who, again according to Herodotus, believed that Africa could be circumnavigated, must have known of the venture, and of another of the early fifth century."