Republic of China's Territorial Claims
Following the Chinese Civil War and its conclusion, the 1949 proclamation of the People's Republic of China (PRC) in Beijing, the nationalist army relocated to Taiwan and set up the Republic of China (ROC) in the 'temporary capital' of Taipei.
Both governments claim to be successors to the Qing Empire and legitimate rulers of the one and only China.
Consequently, the Beijing government considers Taiwan a part of its territory, albeit ruled by a rebel government. Adversely, the Taipei government considers mainland China a part of the Republic, also temporarily under rebel control.
Although most are long since dormant, this stance leaves the island nation with the highest number of unresolved border disputes in the world. Involving 18 other countries and spanning 5,300 km from Tuva to the Spratly Islands, the claimed area would — if it ever came to fruition constitute — a staggering 36,600% increase in Taiwan's territory.
Beijing has since settled most of the border disputes skirting what was once the Qing Empire. Taiwan, however, through its constitution still claims mainland China according to the borders of 1911.