@interesting.always.1 on Instagram: "In the mid-19th century, publishers experimented with ways to depict landscapes beyond flat illustration. One result was the tunnel book - a format made of layered paper panels arranged in a concertina structure. When viewed from the front, the staggered layers created an illusion of depth and distance, allowing scenes to unfold gradually toward the background. A well-known example is the German tunnel book Das Rheingebirge von Bingen bis Lurlei, which depict