The CIA On Time Travel

[Schmoe1]

As cool as time travel would be (me personally, I'd go straight for the cretaceous period and check out some dinosaurs....or maybe get some front row seats to the battle of Thermopylae....or see who really killed JFK....too many choices, I'd probably just be unable to decide)  I just can't reconcile how it would be possible.  Is time a tangible thing that can be traversed, is it even linear?  Is it just a man made unit for structuring out the days and years?  It's basically trying to traverse existence, can't get my mind around it.  Guess that's why I'm not a physicist.