High Quality Content by WIKIPEDIA articles! Declared historic buildings` of Hangzhou are districts, artifacts or buildings legally declared to be "protected". According to the "Regularations of historic districts and historic buildings in Hangzhou" effectivated from 1 January 2005, historic buildings are those artifacts or districts that have lasted more than 50 years, and of significant values for history, science, and art study. In Hangzhou, declaring a historic building requires consulting the urban planning administration bureau, and the real estate administration bureau.