Super guide who knows what he is talking about, i recomend him 100%.
We experienced very much in the 3 hours.

Something I would never normally think of doing and I did swallow hard when I saw the exposed manhole we were ushered to climb into by the side of the freeway .This was after discovering why we needed to bring belts (for our galoshes and not as I thought for stopping your trousers and pants from being pulled down to your ankles after squeezing into the manhole) There was no dank smells, the shallow water beneath our feet was crystal clear in most parts and Vlad our guide was extremely professional . You have to walk long distances bent over and climb through narrow spaces, but we were a mixed sized group of about 10 and we all managed it. My friend and I are in our late fifties and we were fine. There are a labyrynth of tunnels of different shapes and sizes, and as long as Vlad doesn't suffer from any temporary lapse in memory, it is an amazing feat for you to say you travelled this way