The Rybinka river is a major tributary of the Yauza. Though diggers do not often come down to see it. There are no stairs under most of the hatches. We gonna see the historic area of the river - it's a brick circular 3.5-meters chimney with a chamber two meters wide. The authors of the pictures got the place without any stairs or ropes, just using the power of their hands.
This is that very chamber.
Observing the underground waterfall from above.