The Macau Peninsula has a gate built on the northern isthmus, for how long did it serve as a border?
Macau Peninsula Macau Peninsula is the most populous and historic part of Macau. It has an area of 8.5 km² (4 x ) and is geographically connected to Guangdong province, at the northeast, through an isthmus 200 m wide. The peninsula, together with the city centre of Zhuhai, sits on an island separated from the continent by distributaries of the Pearl River. The Border Gate (; Portuguese: "Portas do Cerco" ) was built on the northern isthmus. At the south, the peninsula is connected to Taipa Island by three bridges, the Friendship Bridge ("Ponte de Amizade"); the Macau-Taipa Bridge ("Ponte Governador Nobre de Carvalho"); and the Sai Van Bridge ("Ponte de Sai Van"). The longest axis extends 4 km from the Border Gate to the southwestern edge, Barra (媽閣嘴). There is a western Inner Harbour (內港), and an eastern Outer Harbour (外港). The 93 m Guia Hill (松山) is the highest point on the peninsula, which is, on an average, 50 to . Many coastal places are reclaimed from sea. The Historic Centre of Macau, which is entirely in the Macau Peninsula, became a World Heritage Site in 2005.
Military Frontier The Military Frontier was a province straddling the southern borderland of the Habsburg Monarchy and later the Austrian and Austro-Hungarian Empire. It acted as the "cordon sanitaire" against incursions from the Ottoman Empire.