Abstract: A shelf assembly (10) is adapted to securely mount to a wall (12) adjacent a window frame (14) and in front of a window (18). The window frame (14) comprises an upper portion (20), a lower portion (22) and a pair of identical side elements (24). The assembly (10) includes a pair of bridges (42) mounted to the wall (12) above and below the upper and lower portions (20, 22), respectively, of the window frame (14) and in a position in front of the side elements (24). Each bridge (42) comprises a pair of uprights (26), with each upright (26) having a long vertical part (30), a short vertical part (32) and a central part (34) connecting the long and short vertical parts (30, 32) and angled with respect thereto so as to position the long and short vertical parts (30, 32) in different substantially vertical planes.