What is The Difference Between Art Exhibition, Biennial and Art Fair?

Art exhibitions are as diverse as the art itself. However, the Modernism left us a legacy in which art exhibitions are always considered as those in which an artwork is hangued or displayed in certain space. In some sense, that definitions has led us to think that every space with works of art displayed for the public is an exhibitions. However, there are key differences specially when talking about biennials and art fairs. Here are some tips to know what each one is about.