A memorial hall is a building which serves to remind people of something, again usually people who have died. Memorial halls in the United Kingdom and United States are usually about World War I or World War II. Memorial halls in Germany and Poland are often about the Holocaust, when Nazi Germany killed many Jewish people. Memorial halls in China are usually about the Japanese part of World War II. Among important memorial halls, there are the Nanjing Massacre Museum and the Yad Vashem.