There was no "place" where the Big Bang happened because the Big Bang didn't happen in space as we understand it today–space was created by the Big Bang. In the earliest moments of the Big Bang, the entire universe was just a tiny, hot, dense point and then it began to expand. The expansion of the universe created space itself. So the Big Bang didn't happen "somewhere" (since there was nowhere for it to happen) but rather it was the start of everything.