The Vertical Lidos
From 1880 on, open-air vertical lidos were very popular in London. Requiring little more than some water, a tiled surface and a large diving platform to erect, they sprang up across the city and attracted great crowds.
The largest and most lavish was in St John's Wood. The Wellington Road Vertical Swimming Ponds and Spa was centred around a 45 feet-high cube of freestanding water that visitors could dive into from the tallest diving platform in the world or walk into at ground level. But you had to be careful once inside, because a nasty fall could result if you fell out of the side.
It was, of course, most popular in summer, when people could pay their penny and just stroll in for a refreshing dip, but it froze into a solid block of ice in winter. Nevertheless, it could still be seen surrounded by small children, either because their tongues were stuck to it or, in the bitter winter of 1948, because they were admiring the lithe body of Walter Samuels, who loved the lido so much that he refused to come out and had to wait until the spring thaw of 1949.
Unfortunately, the growing popularity of "baths" or "pools" eroded the visitor-base of the vertical lidos and one by one they closed. The Wellington Road was the last, and only closed in 1957 after it was found to breach section 1.1a of the new planning act, "Gravity: Compliance with". But even today you can meet people who'll tell up they regularly "swam up the Wellington".