A bridge becomes a mountain. Paper turns into rock. Paris discovers a hidden cave in the middle of the Seine. Trace the conception and creation of JRs monumental installation La Caverne du Pont Neuf, a transformative work that reimagines the historic bridge as a vast rocky grotto. Freely accessible to the citys citizens and visitors alike, but only fleetingly. Conceived as a tribute to Christo and Jeanne-Claude on the 40th anniversary of The Pont Neuf Wrapped, the project continues JRs exploration of public art as a shared, democratic experience. Through preparatory sketches, collages, installation photography, and behind-the-scenes documentation, the book reveals how the landmark was transformed into an uncanny geological fantasy. The inclusion of earlier works featuring caves, trompe loeil, and architectural illusion situates this latest endeavor within JRs headline-grabbing career. An interview conducted by Hans Ulrich Obrist with JR, Christos nephew and project director Vladimir Yavachev, and Thomas Bangalter of Daft Punk explores artistic freedom, ambition, and the challenge of realizing large-scale pub