Who landed on the mainland of South America for the first time?

For the most part, Spanish and Portuguese conquerors landed on, or marched into what is now the continent of South America. Yes the Spanish Conquistador Cortes first conquered the Aztec Indians in what is now called Mexico. There is now of course only 2 continents in the Western Hemisphere. North America & South America. South America begins at the southern most part of Panama. For ease of identification, the term Central America is often used to describe the area of Mexico and Panama. This however, is not true geography.