Significance Condensed matter physics owes much of its development to bismuth (Bi). It was the first metal with a Fermi surface that was experimentally identified. Many intriguing phenomena were first discovered in Bi, such as the large magnetoresistance and the propagations of microwaves. For over a century, Bi has been known to be diamagnetic. We have observed an unusual ferromagnetism in pure Bi samples after treatments under certain pathways of pressure and temperature conditions. The ferromagnetism is found to be associated with a surprising structural memory effect in the molten state and the ability for solid Bi to “remember” its liquid structural motifs. This structural memory effect may present an important route in defect engineering for creating materials.