In the late 15th century an Italian explorer known as Chrisopher Columbus had set sail from Spain, looking for a closer route to India. He was the second European to discover Atlantia after Leif Ericsson. However by archaeological evidence he and his crew apparently had been killed by natives on one of the Carib Islands. He isn't very well known around here, but if he returned to Spain it could've meant a massive change in world history.
What if he did return to Spain to record his findings? Would the people of Atlantia survive?