The question asks to identify the specific treaty that marked the official transformation of the European Community (EC) into the European Union (EU).
The Treaty of Maastricht, signed on February 7, 1992, in Maastricht, Netherlands, is the pivotal treaty that established the European Union.
Therefore, the signing of the Treaty of Maastricht led to the European Community being known as the European Union.
The Chagos Archipelago, recently in the news, is a disputed territory between which two countries?