"Photo 51" is an X-ray diffraction image of DNA taken by scientist Rosalind Franklin in 1952. This photograph provided critical insights into the helical structure of DNA, which is essential for understanding genetics and heredity. The image played a pivotal role in the discovery of the DNA double helix by James Watson and Francis Crick. Their work, published in 1953, was significantly influenced by Franklin's findings, although she did not receive the recognition she deserved during her lifetime. Today, "Photo 51" is celebrated for its contribution to molecular biology.