What would be a good thesis statement for a Holocaust essay?What would be a good thesis statement about how inhumane the concentration camps were...

Much of this is going to be driven by what it is you are
going to prove in the paper.  I think that this will be supported by what you have in
your possession in terms of research materials and sources as well as what the task or
assignment is.  If this is for a class, being able to understand the nature and dynamics
of the assignment will assist you in carving out a thesis statement that is aligned with
what is being asked of you.  I think that there are several paths that can be pursued,
but I also feel that this is going to be contingent on what you have, what you need to
do, and with what you feel comfortable writing.  Somewhere between the valences of all
three lies your thesis statement, something that will be up to you to reclaim and
identify.