1: Notionally speaking, where you would wind up if you proceeded to dig a hole through the earth as to come out the other end. (This is mistaken, of course - starting from either coast of the US would put you in the middle of an ocean, as would starting about anywhere in China.) See china syndrome for a possible explanation to the origin.
2: Metaphor for where one can see if they have a clear view of a woman's genitalia - either due to the fact that she is wearing no clothing, or the clothing she is wearing is revealing what's underneath (due to transparency or just that it is ill fitting). Possibly originates by extension of sense 1.
Referring to the Neighborhood In Washington DC. The Top of DC, Uptown NW. Also known as the Gold Coast/ Shepherd Park. The Top of the DC Map. Defines as your location in dc as being at the top of NorthWest DC on the map.
when bye doesn't suffice so you say ALL the way bye, meaning you are completely done with the subject or matter and you are stepping away from it no matter what.
all the way bye i literally can not do this right now no way he just said that all the way bye you're so fake