Merle Liivand is an aquapreneur, plastic pollution reduction advocate, Guinness World Record holder and mermaid. The Estonian-born swimmer holds several Guinness World Records her latest was achieved on April 15, 2023, in a little over 14 hours. Merle swam 50 kilometers using a monofin, a record setting swim for the longest distance swum using a monofin. It's a feat because she swam the distance without using her arms by undulating her lower body up and down mermaid-style.