I'm standing at the rather pointless Mill Hill East tube station.
It sits on its own at the end of a branch poking awkwardly out of the Northern line and it's only wide enough for one train at a time, making the Tube more complicated for everybody.
You might wonder why would they put a station in such an awkward and confusing place?
The answer is they didn't do it on purpose and the clues as to why it's ended up like it has can be seen from up there.
If you look on Google Earth, you can see the Northern line snaking through London between the houses up here to Mill Hill East.
But if you look carefully, you can see that the thin snaking line doesn't stop there.
It keeps going through this row of trees, under the M1 and between these houses in a dead straight line.
Just from looking you can tell that there used to be a train line here.
So what was this train line, and why isn't it a train line anymore?
It was a branch of the Great Northern Railway built in 1867 that went from Kings Cross to Edgware.
