1. Challenging puzzle for adults. Immerse yourself in the intricate world of the 'Summer Day by the River' puzzle. With 438 out of 501 pieces being edge pieces, it is designed to stimulate your mind and deliver a rewarding and complex puzzling experience. 2. Unique edge piece design: The majority of this puzzle's pieces are edge pieces, presenting a distinctive challenge that tests your spatial reasoning and problemsolving skills, offering hours of engaging and thoughtprovoking entertainment. 3. BEAUTIFUL PAINTERLY ARTWORK: Featuring a stunning riversidethemed design, this puzzle masterfully blends nature and artistry into a vibrant, colorful illustration, ensuring a satisfying and visually delightful puzzling experience. 4. CLEVERLY CRAFTED SHAPES: The flat edges of the puzzle pieces subtly hint at the puzzle's dimensions and orientation, adding an extra layer of enjoyment to the assembly process.