Well, its so mini, it's just one image, but as I was on my own, I didn't feel confident in squeezing through the shoulder high window into the tunnels without the worry of getting stuck in sh*t creek lol.
Taken during a recent non exploring trip around Wales, went over the top as the bottom is sealed.
Initially I wanted to do a star trail but the Moon & clouds put an end to that, so I did this instead...
D-UK