The 20 pataca coin from Macau, issued in 1974 in silver, is a commemorative coin dedicated to the Macau-Taipa Bridge, from the former Portuguese colony of Macau (World Coins Macao KM#8). It was created by Decree No. 138/75 of March 11, with the purpose of marking the inauguration of the bridge, and was intended for circulation in the then Portuguese colony. The pataca was introduced in Macau and Portuguese Timor in 1894, during the colonial period, as a unit of account. Initially, it corresponded to the Mexican peso and replaced the Portuguese real, with an exchange rate of one pataca to four hundred and fifty réis. The name “pataca” derives from the fact that the Portuguese traditionally referred to the “piece of eight” as the Mexican pataca.