Pre-Columbian tourism.
The Muslims in West Africa were so intrigued by what was on the other side of the Great Sea, that they began their expeditions into the great unknown. Early reports of these travels are sketchy, but we can be sure that they crossed the Atlantic by 889 C.E.
A Muslim historian and geographer ABUL-HASSAN ALI IBN AL-HUSSAIN AL-MASUDI (871-957 CE) wrote in his book Muruj adh-dhahab wa maadin aljawhar (The meadows of gold and quarries of jewells) that during the rule of the Muslim caliph of Spain Abdullah Ibn Mohammad(888-912 CE), a Muslim navigator, Khashkhash Ibn Saeed Ibn Aswad, from Cortoba, Spain sailed from Delba (Palos) in 889 CE, crossed the Atlantic, reached an unknown territory(ard majhoola) and returned with fabulous treasures. In Al-Masudi's map of the world there is a large area in the ocean of darkness and fog which he referred to as the unknown territory (Americas).
Columbus merely confirmed what he'd learned from globetrotting Andalusians.