Manuka Pool now has a permanent reminder of one of its most devoted swimmers.
Mervyn Knowles dived in on January 26, 1931 - he always said he was the third person to use the pool, after his two older brothers.
He was still swimming there 90 years later, until a few weeks before he died, in 2020.

The friends of the pool have now put up a plaque commemorating the best friend the pool ever had.
"Merv was a stoic. He's old school. He was just straight up and down," according to John "Tav" Taverner who was manager of the pool for what he says were 30 summers of Mervyn Knowles' visits. Mr Taverner's father managed the pool from 1956 before him.
"He never made a single complaint to me. He would always say 'Good morning' and he would always say 'Good bye'," the former pool manager said.
He reckoned that Merv swam the equivalent of from Canberra to Launceston in the nine decades of his laps.
He would do eight laps freestyle, eight laps breast-stoke and then eight laps backstroke, according to his son Jeff Knowles.
"He hated to swim butterfly," the son said.
His father could do the 33.3 metres in 17 seconds, a second slower than his brother who died in the war.
For Merv Knowles, swimming was a mystical experience. "It transcended the day-to-day humdrum of food and job," his son said.
"He never meditated or anything like that but his sacred space was the pool and swimming."
He would arrive promptly at 7.45am and was in the water to swim laps a quarter of an hour later.
At the age of 94, he said: "I used to do 36 laps in half an hour. Now I'm down to about 16."
When he started, Canberra was barely built and the pool was one of the first recreational facilities.
For the many children growing up in the relatively new suburbs of Red Hill, Forrest, Kingston and Griffith, summers were all about Manuka Pool.
Before he died three years ago, Merv would reminisce. He remembered the old diving tower, and the days before the tiered seating was installed when big gaggles of boys would stand on the edge of the pool in trunks which had tops zippered on ("You weren't allowed to wear just the trunks," Merv said.)
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Merv grew up to be the Australian trade commissioner to South Africa, Indonesia and Greece. He and his wife, Beth, had two children - Carol and Jeffrey. The family had moved homes six times within Australia and overseas before deciding to make Canberra their permanent home again in the early 1960s.
Towards the end of his life, Merv swam with a group of older swimmers known as the "coneheads" (so named when two teenagers walked past and one said "I wonder what those coneheads are talking about"). The group gathered each morning in a corner of the pool known as Philosopher's Corner to debate current affairs and interesting topics.
A plaque commemorates the swimmer - and the human being. It says: "Merv, lane one will always be a little empty without you."