Upvote:4
The issue here is more about "us" usually being mostly Europeans, or descendants thereof, and that tends to bias our perception, and our historical writing.
Something put into writing accounts for a great deal, because written documents survive. Our "view" on many historical things is very much influenced on who has written about it -- and if you go back 1500 years or more, you will find there were only a few cultures with a strong written tradition (as opposed to oral tradition, which usually dies together with the culture -- which doesn't mean the culture had less worth, just that its history and knowledge is mostly lost to history).
Our knowledge of Gauls and Germanic tribes of about two thousand years ago, for example, is heavily influenced by the Romans, because they wrote about it and the Gauls / Germans didn't.
So, there have been many people at Lake Victoria before Mr. Livingston, and there is little doubt today that there have been Nors*m*n in Newfoundland long before Columbus...
But they didn't write about it, and others didn't write about them.
Upvote:5
Your question is based on ambiguity of the word "discovered". Let us talk on geography for simplicity. Since the times immemorial, people live almost everywhere on Earth (except Antarctic). Does it follow that nothing in geography except Antactica could be discovered in principle? Then the word "discovery" in geography at least will be totally meaningless.
Instead we give it a meaning. The meaning of "discover" in geography is that the thing is described and made a "common knowledge". Yes, through wide publication. In books and scholarly journals, or by other means of communication. In this sense, Columbus (not Vikings and not American Indians) "discovered" America. Viking's discovery came to nothing and was forgotten. Columbus's discovery led to an enormous transfer of population, plants, animals and information, existence of America became a common knowledge in the Old world.
Same applies more or less to everything else.
Remark. Columbus did not write any books. All his writings are travel logs, reports and letters. Other people wrote books after his discovery.