 In postwar Poland, the government bought most of the land where the camp had stood, and built a large stone memorial there between 1959 and 1962. In 1964 Treblinka was declared a national monument of Jewish martyrology in a ceremony at the site of the former gas chambers. In the same year the first German trials were held regarding war crimes committed at Treblinka by former SS members. After the end of communism in Poland in 1989, the number of visitors coming to Treblinka from abroad increased. An exhibition centre at the camp opened in 2006. It was later expanded and made into a branch of the Siedlce Regional Museum.
