Henlo bernds,
I recently landed a job over in North-Karelia, so I decided to visit one of my favourite place in Finland — Outokumpu. Outokumpu used to be called Kuusjärvi, but changed it name as the mining company Outokumpu became an integral part of the town's identity and townscape. The town literally grew around the mine over the years and as Outokumpu's mine was one of the longest lived mines in Finland the change was irreversable. The town centre is literally just 300 meters from the centre of the mine.
The mine lasted from 1913 to 1989, and because of that early date the envier omental protection and disposal of hazardous waste was to put it lightly neglected, but you know the war and eventual denbts had to be paid somehow...
The hazardous waste was dumbed to a place where a pond called Outolampi was located. After years and years of dumping hazardous waste mostly compromised of waste products from copper production such as ground up rocks, sulphuric acid, asbestos and unneeded metals accumulated to ground and polluted the groundwater. Outolampi was lost beneath all that crap. People thankfully understood what a problem a huge such a pile of waste was and "cleaned" it up. Outolampi was once again freed, but irreversibly changed from this process.
The pH of the lake is somewhere around 1-2, as in the summer it loses water and becomes more acidic. On the plus side, the pond water is great at conducting electricity, as the sulphuric acid has released all the harmful metals in the water. You can see the great colour from Google Maps. The pond releases a great rotten egg stench in the summer, but in the winter it is calm and not even that horrific to look at. Only with a strong flashlight and clear ice, you can see what horrid water lurks beneath you. I visited the lake at a prime time as there was no snow and a freezing weather that had formed small "frost flowers" on the ice. To you guys, this might seem like a banal thing to show, but I fucking love this little pond. Locals even call it sumppi (ie. coffee) for it's dark and mysterious colour. Trees around the lake are dead, but the small island on the lake has some majestic birches on it.
I would write more about this amazing pond, but my sauna is ready :3