Eryi-lou is a so called 'double-donut shaped tulou' that is located at  Xiandou Country, Huaan County, Zhangzhou City, Fujian Province. It was built in 1770 and has been resided by Jiang family since then. (As now, about 40 households, 200 people live here.) It is a 4-story tulou, which is 18m high and more than 70m wide. It consists of 12 dwelling units and four other bays for entrances and the communal ancestral shrine. The typical floor of each unit has 4 rooms. One peculiar element in the Eryi-lou is a communal private corridor (Yintong-lang) at the 4^th floor, encircling the perimeter of the whole building, which is made for escape in case of emergency. The Eryi-lou is one of the representative and largest tulous, even though not a typical one in that each floor of a dwelling unit of a tulou generally has 'the one bay, one room ' system.