Sunday morning in the Megatron

The Megatron! Somewhere I've wanted to explore for quite a long while. It's the enormous underground network of culverts and drainage systems that takes water from two local rivers (the Sheaf and Porter), underneath the railway station and adjoining areas, into the larger River Don.  
These days you can take a guided tour through much of the network, run by the wonderful Sheaf and Porter Rivers Trust. The Trust works to improve the environment in and around the rivers, and also promotes the case for opening up more of the waterways, historically culverted and hidden for much of their length in the city.
Much of the Megatron network dates back to Victorian times, and certain parts to a a century or two before that.  You can find clues to past industrial activities down there, including old crucibles (main image), grindstones and pieces of cutlery.
It's described as an 'urban caving' tour, and parts of it are hard work. There are short sections where you have to crawl on hands and knees through a very low tunnel and others where you're wading in water up to knee height (or higher, depending on recent rainfall, or on whether you fail to spot an unexpected underwater hole). For much of it, you're walking on slippery brickwork or stones.  So after the two hour circuit, I felt I'd had a good workout. I did manage to stay upright, and to avoid filling my wellies with water. The extras provide some glimpses, though I spent much more time keeping myself upright than taking any photos.
It was an oddly exhilarating experience. I think that's partly down to the sheer enthusiasm of the guides and volunteers, and partly to the sense of exploring somewhere usually so hidden and neglected. We learned a fair bit about wildlife in the network (bats currently in some parts, sometimes otters recently), as well as about the history. There's a bit more about the Trust, the tours and its general work here:
https://www.sheafportertrust.org/guided-tours

There's a more thorough account of the history here:
https://sheffielder.net/tag/megatron/

Now for a quieter afternoon...