The 3D puzzles are scaled to represent the different sizes of the planets, so Saturn and Jupiter are represented as 108pc puzzles, Uranus and Neptune as 72pc, Earth and Venus as 54pc and Mars and Mercury as 27pc puzzles, totalling 522 pieces in all. Each puzzle has curved, high quality plastic pieces, which are numbered on the inside for easy assembly. Each “planet” comes with its own stand and the whole set can either sit on the colourful “Solar System poster (which includes facts about each of the planets), or be suspended by thread. The set also includes a kit which assembles into a “sun” mobile, and a fact-filled information leaflet for all budding astronomers out there! Suitable for ages 7 years and up. This puzzle uses unique plastic pieces, which slot together to build this sturdy and strong model. No glue required! Each puzzle piece is printed with a number on the reverse side, so you can either assemble the puzzle by eye, or just by following the numbers.