A pyramid scheme is a fraudulent investment or business opportunity that involves recruiting new members to pay money in exchange for the promise of rewards, which are actually paid out only to those who recruited them. The structure of such schemes resembles a pyramid, with each level consisting of multiple participants and one at the top earning the most profit. Eventually, as the scheme collapses due to lack of new members or resources, the majority of investors lose their money while only a few individuals at the top benefit. Pyramid schemes are often disguised as legitimate business opportunities but ultimately result in financial loss for those who participate.