Where is Hell?

Why when people have a near death experience are they never standing outside of Hells gate? Just wondering. Is that so they go back to their bodies and do good? But if they think they are going to go to heaven anyway, why would they think they would have to change anything. I know your soul goes somewhere. But do we all just go to "Heaven" or do the Gates of Heaven and Hell look the same? I guess as long as we are living we will never know.