The abandoned Nazi underground city hidden beneath beautiful countryside

Pniewo, Poland —

At first glance, there’s nothing unusual about the countryside around the small Polish village of Pniewo. The landscape is typical of the Lubusz Voivodeship region: vast fields of yellow crops beneath big skies, broken only by the occasional patch of forest.

It looks serene, but hidden below is a darker story — a Nazi underground city.

Festungsfront Oder-Warthe-Bogen, or the Ostwall, is a fortified subterranean complex built before World War II as Adolf Hitler sought to secure Germany’s eastern frontier from Poland and the Soviet Union.

Between the Oder and Warta rivers, which today form part of the German-Polish border, the facility remains largely intact: a sprawling maze of tunnels, underground railway stations, combat facilities and massive shafts covering abou