 Complete the following phrase:  A fortified structure at No.55 Ha Pak Nai, which is a declared monument owing to its connection to the revolutionary movement of modern China under the leadership of Dr. Sun Yat-sen. Hsing Chung Hui Revive China Society members, who were KMT, stationed at Lower Pak Nai for preparation of overturning the ruling of Qing authority and conducted bomb tests. Luo 1971:37 The structure was built by a core member of Hsing Chung Hui named Tang Yam-nam around 1910. It was the only solid evidence correlating the 