markian writes "Canada is set to switch to new banknotes that last 2.5 times longer than paper money. High-tech features include metallic imagery in a transparent area, raised ink, transparent text, and hidden numbers. 'If you look through the frosted maple leaf emblem at a single-point light source and hold it close to your eye, you'll see a hidden circle of numbers that match the face value of the note.' The Bank of Canada has more information on the subject. Now if we can just get rid of the penny..."