I think this hasn't been answered because it's not a very well posed question. It sounds like the beginning of a joke, in which case I'm very interested in hearing the answer. read more
On the serious side, it's safe to say that ocean trenches are the result of plate tectonics. They occur where down-going plates are subducted beneath overriding plates. Ocean trenches are the deepest locations in the ocean, the deepest being the Challenger Deep, located within the Mariana Trench. read more