MRU

Międzyrzecki Rejon Umocniony (Międzyrzecki Fortified Region) is a huge system of German fortifications built in the 1930s on the Polish-German borderland. Located in the Odra and Warta bend, it stretched for almost 100 km. Its task was to defend the access by the shortest route to the capital of the Third Reich. Several dozen battle shelters, fortress weirs, sliding and swinging bridges, many tactical channels, and vast floodplains were constructed. The whole was divided into three sections: Southern, Central and Northern. By Hitler’s decision, this gigantic construction project was never completed.
In the Central Section, apart from the battle shelters, the most important element of fortifications was the connecting system of underground tunnels with a total length of over 30 kilometers, equipped with underground stations and storage chambers. In 1945 the fortifications were captured by Soviet units and then blown up and stripped of their armour elements.
Much has been destroyed, but not everything…
In the central part of the site several fortified groups survived, as well as a priceless system of underground tunnels, in which in 1980 Europe’s largest bat sanctuary was established (every year over 30,000 of the winged mammals hibernate there). In the Scharnhorst Stronghold Group in Pniewo, one of the best preserved in the whole MRU, on January 1, 2011 the local government of Międzyrzecz Municipality established the Museum of Fortifications and Bats. The group consists of three above-ground collar shelters numbered 716, 716a and 717, each with an underground barracks and warehouse complex. The interiors in bunker 717 have been recreated with furnishings for visitors in mind. However, what attracts tourists is the underground system.
The year-round tourist route includes two variants of sightseeing: a short route – up to 1.5 hours and a long route – up to 2.5 hours of wandering. On request, there is also an extreme route with the time of staying in the underground for up to 8 hours. Guided tours are provided by qualified guides. Tourists, in addition to the open exhibition of military equipment, also have at their disposal an observation tower, a souvenir stand, a bar and a car park

Museum of Fortifications and Bats
Międzyrzecz Fortified Region (Festungsfront Oder-Warthe-Bogen)
War Group Scharnhorst
The largest post-military underground in Europe

In the area:

http://geopark.muzakowski.pl/

http://www.leknica.pl/leknica.pl/turystyka/informacje-praktyczne.html

https://www.park-muzakowski.pl/

https://lipinki.zielonagora.lasy.gov.pl/sciezka-geoturystyczna

https://przygodaznysa.eu/

http://kajaki-leknica.pl/

http://www.ceramikapogranicza.eu/szlak-ceramiki.html