occupation, the Germans destroyed some of the city's historic buildings to erect new structures in the Nazi style. The Germans built a huge secret dynamite factory (DAG Fabrik Bromberg) hidden in a forest in which they used the slave labor of several hundred forced laborers, including Allied prisoners of war from the Stalag XX-A POW camp in Toruń. In 1943, local Poles managed to save some kidnapped Polish children from the Zamość region, by buying them from the Germans at the local train station. The Polish resistance was active in Bydgoszcz. Activities included distribution of underground Polish press, sabotage actions, stealing German ammunition to aid Polish partisans, espionage of German activity and providing shelter for British POWs who escaped from the Stalag XX-A POW camp. The Gestapo cracked down on the Polish resistance several times. In spring 1945, Bydgoszcz was occupied by the advancing Red Army. Those German residents who had survived were expelled in accordance with the Potsdam Agreement and the city was returned to Poland, although with a Soviet-installed communist regime, which stayed in power until the 1980s. The Polish resistance remained active in Bydgoszcz. Post-war period In the same year 1945, the city was made the seat of the Pomeranian Voivodship, the northern part of which was soon separated to form Gdańsk Voivodship. The remaining part of the Pomeranian Voivodship was renamed Bydgoszcz Voivodeship in 1950. In 1973, the former town of Fordon, located on the left bank of the Vistula, was included in the city limits and became the easternmost district of Bydgoszcz. In March 1981, Solidarity's activists were violently suppressed in Bydgoszcz. Currently, Bydgoszcz is the biggest center of NATO headquarters in Poland, the most known being the Joint Force Training Centre. Main sights The oldest building in the city is the Cathedral of St Martin and St Nicolas, commonly known as Fara Church. It is a three-aisle late Gothic church, erected between 1466 and 1502, which boasts a late-Gothic painting entitled Madonna with a Rose or the Holy Virgin of Beautiful Love from the 16th century. The colourful 20th-century polychrome is also especially worthy of note. The Church of the Assumption of the Holy Virgin, commonly referred to as "The Church of Poor Clares," is a famous landmark of the city. It is a small, Gothic-Renaissance (including Neo-Renaissance additions), single-aisle church built between 1582 and 1602. The interior is rather austere since the church