Velella (also known as sea raft) washed up on a beach in Ramatuelle, south-eastern France. It is a cnidaria – part of the group that includes jellyfish and sea anemones. A velella travels by means of the transparent ‘sail’ protruding from its back, which catches the wind [• This caption was amended on 19 April 2024 to remove a reference to cnidaria being part of a botanical, rather than animal, group]
Photograph: AFP/Getty Images