Christo's "Valley Curtain" proposal employs mixed media collage including paper, fabric, pencil, and crayon to visualize an ambitious environmental installation concept across a Colorado valley landscape. The work demonstrates the artist's characteristic approach to presenting unrealized large-scale public projects through intimate, detailed drawings that combine technical precision with artistic rendering. Presented in a custom Plexiglas box frame, the piece exemplifies how Christo documented and promoted his monumental temporary artworks that fundamentally transformed natural environments through the strategic deployment of fabric and materials.