Pool swimming in : 25 m vs 50 m

Lane discipline, stroke mechanics and public-bath access — the lowest-friction way most people first meet structured water time. Pool swimming is the controlled version of a human skill that used to be learned in rivers and harbours. Chlorination, lane ropes and depth markings turned a public-health project of the late nineteenth century into the default first water classroom.

World Aquatics (formerly FINA, founded 1908) still writes the competition rulebook, but most pool hours are not racing: fitness laps, school lessons and municipal recreation. The same 25-metre basin can hold a masters set at 06:00 and a learn-to-swim class at 16:00. This atlas treats the pool as infrastructure — access, etiquette, coaching lineages and the gap between a public bath and a FINA-standard 50-metre hall — not as a race preview. Open-water and competitive chapters sit beside it.

Municipal and club pools publish lane books before open-water leaps. Red Cross / federation lessons gate beginners — a dive card is not a pool pass. Indoor 25 m is year-round; outdoor seasons follow local climate. Pool swimming mapped for mechanisms, locale notes and limits. Pool swimming sits in the swim atlas — mechanisms, locale notes and limits, not slogans.