1. some say 50, some say 52.. i'll go with 50 though.
2. Discovered for who? i mean, native americans discovered it way before any europeans.
but, by America, do u mean USA or the continent America?
Leiv Eriksson were teh first european to make it to America, to be more specific, the east coast of canada, which he called Wineland.
Christopher Columbus were on several of the islands in the mexican golf.
And, because Peter Griffin is always right, im gonna go with Dick Yorke discovering the United States of America

(im probably the only one laughing now lol)