For more than sixty years, party-goers trekked across one of Auckland's wildest west coast beaches to Te Ana Ru cave, to dance on a kauri floor. It was built by loggers, and when not in use lifted up to the cave ceiling to save it from the incoming tide. It's been another sixty years since people took part in one of the famous dances at the 'ballroom cave'. But the legend intoxicated two Wellingtonians, Jenny Gillam and Eugene Hansen, who visited it while on an Auckland Regional Parks Residency last summer. They've been working on an exhibition inspired by Te Anu Ru for over a year, though they were delayed twice by Covid 19. Now finally Jenny and Eugene are about to unveil The Thrum of the Tide, a piece that includes a six-hour long soundscape. Lynn Freeman asks them how they first heard about the ballroom cave. The Thrum of the Tide premieres on Saturday at the Titirangi War Memorial Hall as part of the Auckland Arts Festival.