In which country was the film Nanjing filmed?

Nanjing, which was not shot by China, is a documentary film which was collected and shot by Americans. The director: Bill Gutentag

More than a dozen westerners risked their lives to establish a safe zone in Nanjing in December 1937, which protected 2, China refugees. One of them is the story of John? The 4-minute film shot by Maggie's westerners with a small 16-mm camera recorded the brutality of the Japanese army, which made people's backs chill. It was very shocking.