sentences:  Zhongshan Hall has always been one of the formal reception areas for welcoming foreign guests and diplomats.Former guests have included US President Richard Nixon, Korean President Syngman Rhee, President of South Vietnam Ngo Dinh Diem, Philippine President Carlos P. Garcia, Iranian Shah Mohammad Reza Pahlavi, and others.Zhongshan Hall has also hosted memorial ceremonies such as the signing of the Sino-American Mutual Defense Treaty and three formal inauguration ceremonies of the second, third, and fourth presidency and vice-presidency of the Republic of China.