Maybe, Mansa (King) Abubakari II of Mali, a black muslim, sailed from West Africa to northeastern South America almost two hundred years before Columbus. King Abubakari, after learning from arab scholars that there were lands on the west side of the Atlantic, became obsessed with the idea of extending his kingdom into these Terra Incognita. Abdicated his throne and went to his adventure never coming back. Mobilizing resources of his empire to hire arab shipbuilders from Lake Chad to build a fleet, the king and his crew sailed down the Senegal river and across the Atlantic in 1311. Aparently he sighted the north coast of South America but landed first in Panama. Supposedly, king Abubakari II and his entourage travelled south from Panama and settled in the Inca Empire.
The great Musa Mansa, the succesor or Abubakari II is the original source of this history, while describing to the governor of Cairo in 1324 (back from his fabulous pilgrimage to Mecca) as recorded by historian Chihab al-Umari (Damascus, 1300-1384) who was there few years after the visit of the wealthy king. He wrote:
The ruler who preceded me did not believe that it was impossible to reach the extremity of the ocean that encircles the earth (meaning the Atlantic): he wanted to reach that (end) and was determined to pursue his plan. So he equipped two hundred boats full of men, and many others full of gold, water and provisions sufficient for several years. He ordered the captain not to return until they had reached the other end of the ocean, or until he had exhausted the provisions and water. So they set out on their journey. They were absent for a long period, and, at last just one boat returned. When questioned the captain replied: 'O Prince, we navigated for a long period, until we saw in the midst of the ocean a great river which flowing massively. My boat was the last one; others were ahead of me, and they were drowned in the great whirlpool and never came out again. I sailed back to escape this current.' But the Sultan would not believe him. He ordered two thousand boats to be equipped for him and his men, and one thousand more for water and provisions. Then he conferred the regency on me for the term of his absence, and departed with his men, never to return nor to give a sign of life.
The historian, Ivan van Sertima (Guyana, 1935-2009) in his book They Came Before Columbus (Random House,1976) was one of the suporters of this interesting theory.