The No. 38 Sipailou on the foot of Wushan Mountain is one of the most popular sites for cooling off from summer heat. It is an air-raid shelter that was established in the 1970s. On May 10, an exhibition featuring the aerial defense history in the past 100 years in Hangzhou kicked off at this shelter.

Around 1,000 ㎡ of the air-raid shelter has been opened as a summer retreat since 2003. During the 1-month display, the underground tunnel will be opened to the public for the first time. Precious photos, collections, and videos are on display.