OpenFlySwims, the long-distance butterfly swim ledger

Field notes

OpenFlySwims applies a stated filter to a narrow endurance-sport record: swims must exceed 10 kilometres, have significance beyond training, and follow typical marathon-swimming rules including no wetsuit. Entries are accompanied by sources, while the site organizes the material into records, swimmer pages, a hall of fame, and a map. The map also marks some unfinished butterfly challenges that remain open to future finishers.