If jesus is the only way into heaven...?

how did people before jesus's day get to heaven? what about the rest of the world? i think it wouldn't make much sense for a loving and merciful god to allow wonderful people who were truly good at heart--or anyone else, for that matter--to go to hell simply because they didn't know or believe in jesus as the son of god and all that.. besides, nobody deserves eternal torment like hell, no matter what he/she has done in life. the idea of doing that to someone for any reason is ridiculous. whatever happened to unconditional love?