The issues start at the beginning of the Mulan teaser trailer when we see two large, round, yellow homes. These communal buildings are called tulou, or Fujian Tulou, and they are unique to southeast China’s Fujian province, home of the Hakka ethnic group. According to CNN, the first tulou were built towards the end of the Song Dynasty (960 AD-1279 AD) and it seems they didn’t become widespread until starting in the 15th century. You can see them in the first look trailer, below.