Toronto's most popular swimming pool was once the largest of its kind in Canada and, reportedly, the entire world.

Every summer, thousands of bathers in Toronto flock to Lake Ontario to cool off and get outside — but a good number of them won't be swimming in the lake at all.

Instead, they'll be visiting the Gus Ryder Pool at Sunnyside Beach which, at nearly 100 years old (99 this month, to be exact), remains one of the city's most popular summertime swimming destinations.

Swimmers take a dip in the heated and chlorinated pool circa 1926. Photo from City of Toronto Archives.

First opened in 1925, the pool was a rare luxury: one of the first heated and chlorinated outdoor pools in the city, which allowed bathers to take a dip even when the lake water just a few feet away was too frigid.

The pool, then called "The Tank," was one of the first attractions to be built for the then-wildly popular (and now defunct) Sunnyside Amusement Park, which resided just southwest of the King, Queen, Roncesvalles intersection.

A very packed Gus Ryder pool in 1926. Photo from City of Toronto Archives.

With capacity for 2,000 swimmers (which has since been reduced by the city to 850), it's been reported that around 28,000 people turned up for the pool's opening day, with special police enlisted to keep poolgoers outside of the gates.

A 1960s-era aerial view of Gus Ryder pool and Sunnyside beach. Photo from City of Toronto Archives.

The pool measures in at a whopping 91 by 21 metres (or 100 by 23 yards), which, at the time of its opening, set the record for the largest outdoor pool in the entire country.

While records are hard to find to accurately confirm the claim, it's also been reported that the pool was the largest of its kind in the entire world in 1925.

Sunnyside Amusement Park was, in its time, a crowning jewel for the city, boasting a rollercoaster, carousel (which was later sold to Disneyland where it exists to this day) and dance hall — though now all that remains of its former glory is the pool and iconic bathing pavilion, which was constructed in 1922, three years prior to the pool's opening.

Crowds at Sunnyside Beach and Bathing Pavillion in 1924, one year before the pool was built. Photo from City of Toronto Archives.

Originally named The Sunnyside Natatorium, the pool was renamed to Gus Ryder in 1980, to honour the champion swimmer and Canadian Sports Hall of Famer, who was present on the day the pool opened.

The number of swimmers heading out to the Gus Ryder pool has declined over the years, with the City of Toronto reporting that the pool saw just under 69,000 swimmers for drop-ins and 261 swimming lesson registrants in 2023.

In spite of this, the Gus Ryder Pool holds strong as one of the city's iconic landmarks — still serving as the perfect summer day retreat nearly a century later.