Usually when someone says "holocaust" he refers to nazist's genocide whose victims were mainly jews.
http://en.wikipedia.org/wiki/Holocaust
about the lunar landing, i dunno much, but some people believe that the videos shown are not credible for various reasons. One of them point out that stars are not visible and since there is no sky on the moon it is "obviously" a hoax. Those people probably don't know that the sky itself has nothing to do with the fact that stars are not visible during daylight. The astronauts landed in a place that was exposed to the light of the sun and the reflected light from earth, plus the camera used was an old model, it is only obvious that stars are no visible.