The Central German Lake District (German: Mitteldeutsches Seenland) is an area of artificial lakes created from former open-cast lignite mines in Saxony, Saxony-Anhalt and the northeasternmost parts of Thuringia around Altenburg. The area is somewhat ill-defined and the immediate surroundings of Leipzig, by far the biggest city in the area are separately marketed as Leipziger Neuseenland ("Leipzig Lake District" or more literally "Leipzig new-lake-land")
The area has been notable as a centre of lignite mining for over a century. While lignite, a lower quality (and geologically "younger") type of coal than the "black" coal found in the Ruhr area, was not a prime priority during the early phase of German industrialization, the loss of territory, industrial capacity and coal deposits as a consequence of World War I led to the development of more mining in the area. Later Nazi era efforts to become "resource self-sufficient" led to the widespread adoption of new chemical processes such as Fischer-Tropsch synthesis (developed in the 1920s) which allows the production of complex carbohydrates (including liquid fuels) from low quality carbon and water. As East Germany (styling itself the "German Democratic Republic" or GDR) lacked natural resources besides lignite, production was further intensified and new processes were developed to turn the low quality lignite into coke suitable for metallurgical uses. The East German chemistry industry largely headquartered in this region had initially used Soviet petroleum, which the GDR could buy below world-market rates until a change in policy by the USSR forced the GDR to pay market rate, making the dependence on lignite even more acute. In its 40 years of existence, the GDR, a country of less than twenty million people, came to be the biggest producer (and user) of lignite and energy self-sufficient at the price of devastating the local environment, relocating some 50 000 people for the open pit mines and a characteristic smell from the burning of lignite and the exhausts of the Trabbi cars that still form part of the negative stereotypes westerners have about the east. As lignite in general tends to have a pretty high water content (30-60%), it is not economical to transport it long distances, meaning most is burned at nearby power plants.
During GDR times, it was however also used for metallurgical and chemical purposes and there are to this day factories turning the coal dust into briquettes for use in home heating. In Germany, one can buy lignite briquettes at stores like Obi. A further problem of lignite is its high sulphur content, which when burned produces substances responsible for acid rain. Central German lignite is particularly bad in that regard. During the GDR times, the "solution" was to just build high smokestacks to disperse the pollution over as wide an area as possible (including adjacent countries) but these days the power plants have been fitted with scrubbing devices.
As the lignite often lies under several dozen meters of overburden (which had to be removed) and well below the natural water table, the water table had to be lowered during mining, creating all sorts of problems. Once a pit had been exhausted, keeping the water table lowered would no longer be sensible and thus they were either filled back up with overburden (still leaving a height difference of the coal seams which could reach several meters) or left to fill up with water. However, the groundwater would seep through minerals like pyrite oxidizing them and creating low pH waters known as "acid mine drainage" which would severely damage and disrupt the local ecosystem and make the lakes unusable. In at least one case, GDR authorities used wastewaters from aluminum production (which has a very high pH) to neutralize the acid water, but in most cases water from local rivers is used to flood the holes left by the mining to prevent the pH from falling too low. Another method of environmental remediation is adding Calcium Oxide to the water to neutralize the pH. Today many of the lakes have relatively clean water and are a habitat for several species of freshwater fish. Naturally any body of water where swimming is officially allowed has to undergo rigorous testing of the water quality ensuring safe swimming.
The end of the GDR and reunification suddenly changed the circumstances and it was clear that lignite mining would have to be scaled down. However, burning the cheap fuel in the nearby power plants still remained an incredibly profitable endeavor, so the Treuhand, a holding company set up to privatize the former "Volkseigene Betriebe" (Literally: "people owned enterprises"; de facto state-owned companies) ultimately found a buyer for the profitable parts of mining and power generation doing business under the name MIBRAG (Mitteldeutsche Braunkohlengesellschaft or central German brown coal company). Still the damages left behind by the mining and the transformation from open cast mines into lakes for touristic use as well as making sure damages to the people in the area and the environment were kept to a minimum were the task of a new state-owned enterprise, the LMBV (Lausitzer und Mitteldeutsche Bergbau-Verwaltungsgesellschaft Lusatian and Central German mining administration company) which is also responsible for the Lusatian Lake District. In the light of the CO<sub>2</sub> emissions caused by the burning of lignite and Germany's commitment to becoming carbon neutral some time in the 21st century a plan was drawn up to end the mining and burning of lignite by or before 2038 with the affected areas getting billions of euros in federal subsidies to ease the transformation. There are plans for various infrastructure improvements (touristic and otherwise) in the area in the course of this transformation.
Leipzig and Halle are railway nodes with services in all cardinal directions, but there are also stations close to some of the lakes
There are still a handful of mines actively producing lignite for nearby power plants and there are usually lookouts where you can observe the goings-on.
There are a bunch of campsites near many of the lakes
The language that'll get you the furthest is of course German - most of the visitors are German, so the tourism industry mostly caters to them. English proficiency tends to be lower than in the West. During GDR times Russian was the mandatory first foreign language in schools and some schools in the area still teach it as an optional second or third foreign language. Leipzig as a growing university town has a lot of transplants from the West and an international student scene and that'll certainly be evident during events such as the Highfield Festival.
There have in the past been accidents related to the collapse of heaps of overburden loosely deposited at some other point and in a few cases even of "natural" ground collapsing due to the activities of mining and flooding. The LMBV is responsible for the safety of the area and puts up "do not enter" signs in areas where a danger to life and limb from earth movements cannot be discarded. Still, there remains a small residual risk as evidenced by the collapse of the ground below several houses in Nachterstedt, Saxony Anhalt in 2009 which killed three people whose bodies were never recovered.