A bit Shite this, but went to investigate some old tunnels in our local park i got told about recently.
I never knew they existed before, and i've lived in the area for 38years
The 2 tunnels run parallel to each other.
I think they could be water outlets for the old mill, then ran into a lake where the park is located now.
Very stonky in places, and averaged about 3foot in height throughout (lowest was a mere 18 inches ),
except the entrance part - that went to about 10foot high.
Plenty of spiders were living inside.
i didn't get to the ends due to time, but will find out where they come from / lead to proper another day.
A Few Pics