The Milan Triennial (Triennale di Milano) was established in 1933 as a 3 yearly art and design exhibition held in Monza and then in Milan.
History
The event started as a biennial event in Monza in 1923 and then transferred to Milan where was intended to be held every three years, last a few months and to invite global contributions. These similarities meant that it was recognised by the Bureau of International Expositions (BIE) from 1933 until 1996
Since 1923 it has been held in the Palazzo dell'Arte, Milan with the 2016 event to be hosted there and also other Milanese venues
References
Milan Triennial Wikipedia(Text) CC BY-SA