Rainbow flag Alliance (ICA) designed an international co-op symbol and a flag for the first "Co-operators' Day," which was held in July 1923. After some experiments with different designs, a famous French cooperator, Professor Charles Gide, suggested using the seven colours of the rainbow for the flag. He pointed out that the rainbow symbolized unity in diversity and the power of light, enlightenment and progress. The first co-op rainbow flag was completed in 1924 and was adopted as an official symbol of the international cooperative movement in 1925. In 2001, the ICA's official flag was changed from a rainbow flag to a
Rainbow Vent Field originate at the Rainbow Massif. Regarding macrofauna, the Rainbow Massif has been supportive of many kinds of decapods and mollusks, such as Alvinocarididae and Bathymodiolus respectively, feeding where nutrient-rich vent fluids interact with the cold bathypelagic waters. Rainbow exhibits fossils of many kinds of vesicomyid and thyasirid shells. Fossils have been dated at other sites on the Rainbow massif, with Ghost City containing gastropod and clam remains that are aged at nearly 111,000 years old. Shell-rich carbonates have been found at Clamstone, which may be as old as 25,000 years. Rainbow, as with all other deepwater vent systems, is a