My friend and I visited these two drains a little while back. Numbers 1-3 are from one drain, numbers 4-8 are from a drain that feeds into the first drain via a short open ditch.
And I'm sorry about the crappy quality, the pictures were taken by a phone. Also this was our first drain exploration ever. Anyway:
The entrance to the first drain.
The entrance to the second drain.
Someone had an interesting day: "Dough R. is going to fuck all the sluts in the house" XD
I played around with the picture settings on this one.