MD,
        Although I do not believe there is a "universal timeline" that
can represent all the different aspects of our histories, may I suggest
you look at Leone and Silberman's book Invisable America:1995 published
by Henry Holt. It chronicles some of the underrepresented events in
history from the 15th century to the 20th in short essays contributed by
many folks from a variety of disciplines.
liz west