Mintage: 4,299,000

Years of issue: 2003 Information: In 1953 in a Cambridge University laboratory, Francis Crick and James Watson discovered DNA, changing the face of biological science in the process. They found a twisted strand of deoxyribonucleic acid, intertwined in such a way that could pull apart, replicate theselves and pass their genetic code from old cells to new. This reverse design pays tribute to this 'double helix' structure and marks the 50th anniversary of the discovery.