In his old age he became a communist and during the cold war it was just too tough to be a communist in the US. He went to Ghana after it became the first African country. DuBios has worked for African independence all his life, and was invited to enjoy it by Kwame Nkrumah, his old friend, and Ghana's first president.
In the late 1400s and 1500s, the main reason for exploration in the New World was the need for alternate trade routes. They have no idea the Americas even existed, however.
The answer to your question is,
Continents on the east side could fit snugly against those on the west.
-Mabel <3