In 2021, invited by the French artist Thomas Mailaender for a residency at Tuba Club in the Calanques National Park in southern Marseille, Julien Berthier took an old boat and topped it with a calanque-inspired slab of rock sculpted in the same resin as the boat's hull. Once placed in the water, the work became practically invisible and gave the installation its title. Continuing his reflections on landscape, Berthier's book "The Invisible Journey" incorporates the rock-boat across a set of postcards, in the same manner: both visible and invisible. Low tech by choice, Berthier cut out images of the boat manually, then glue them directly to the postcards. The rock-boat thus embarks on a tour of various places and eras, accompanying the travel accounts of strangers.