TIL that In 2011, a Chinese construction company called Broad Sustainable Building built a 30-story hotel called the T30 in just 15 days in the city of Hunan. See comments for the rest.

https://www.eco-business.com/news/30-storey-building-constructed-in-15-days/#:~:text=This%2017%2C000m2%20hotel%20constructed,the%20floors%20built%20around%20it

https://www.reddit.com/r/todayilearned/comments/1671rh2/til_that_in_2011_a_chinese_construction_company/