Where can I watch Aven in Spain?

Performance, 23 September 2005, at Zoersel, Seppenshuis. Avens are relics from prehistoric times (3000 BC). They are natural cavities in the limestone soil that have been washed out by water. The early inhabitants used those cavities as a quarry from which they extracted the clay for their pottery. When the clay ran out or had become too difficult to reach these caverns were used as depositories for food. Usually an AVEN was connected to an underground vein of water. I saw AVENS like this in Cambous, Languedoc. They date from 3000 BC. "I think they’re wonderful. Time and time again it surprises me that as soon as I perform a work existing in my head, it begins to lead a life of its own. During the try-out I discovered that an AVEN could also be the crater of a blue meteor fallen from Sirius into our garden or just as likely a hole in the ground caused by the impact of a poisonous gas bomb."