This is incredible. Apparently, the Royal Mail used to run an underground train network in London of mail trains and the entire system is now sitting derelict.
Some intrepid individuals managed to break into the abandoned system and walk it’s entire length, taking tons of pictures along the way.
Here’s an excerpt:
For as long as i can remember, explorers have joked, discussed, cried themselves to sleep over possibilities the Post Office Railway could be explored. Those keen to attempt entry desperately clawing at every scrap of information like a starving hobo snacking on bread crumbs. Just the idea of access, let alone the task of traversing the line seemed fraught with impossible obstacles and doubt.
With all the abandoned postal depots now either converted, or with a foot thick dump of concrete covering what would have been access to the treasures blow all potential avenue of access pointed solely to the infiltration of live postal depots. In other words, somehow getting into site, the main building, working your way down an unknown route and series of passages, locked doors, workers and alarms until you somehow found your way into the basement and with it the depots Mail Rail station. I.e, impossible.