The International Triennial Ecology and Art (ECO Triennial) was established in 1980 by Maribor Art Gallery. Addressing environmental issues first as a topic and later on contextualising them in terms of ecology and social change, this triennial has been organised regularly till 2006. The gallery reconceptualised the event and the next triennial takes place in spring 2021 in the complex of the former MTT textile factory in Maribor. Under the title A Letter to the Future its main exhibition is curated by Alessandro Vincentelli (UK, Greece). EKO 8 is accompanied by a vast discursive programme, focused on the city and the urban community and realised in co-operation with the Centre for Creativity and Igor Zabel Association for Culture and Theory as partners, and building on the institutional network in the city itself.
The Triennial Ecology and Art was launched as a Yugoslav exhibition, inviting artists from the whole country and curated by the established selectors as they were called at the time (Zoran Kržišnik, Meta Gabršek Prosenc, Aleksander Bassin, Muhamed Karamehmedović, Marijan Susovski, Irina Subotić, Berislav Valušek, Ješa Danegri, Nermina Zildžo, Igor Zabel, and others). After the dissolution of Yugoslavia it continued as a curated international event. Among the curators were Werner Fenz (AUT), Želimir Koščević (CRO), Ernesto L. Francalanci (IT), Katalin Timár (HU), Nancy Buchanan (ZDA), Anda Rottenberg (POL), Maria Vassileva (BOL), and Janka Vukmir (CRO).
During its last editions the triennial "with its exhibition format and ever-expanding focus, had somehow lost sight of its mission and had become unresponsive to changes in both the art ecosystem and wider society" and was therefore suspended from 2006 till 2020 when it was reconceptualised.