London during the 18th century wasn't exactly a comfortable place to live. With no air conditioning to speak of, summers turned brutally hot, and the streets were downright filthy. Naturally, plenty of residents dreamed of cooling off with a good swim. The problem? Major waterways like the Thames were just as unsanitary as everything else. Clearly, the city was ripe for a fresh, bold idea related to swimming — and on May 28, 1742, that's exactly what arrived: the world's first indoor swimming pool.
Indoor bathing spots had existed since the previous century, with establishments like the well-known Bagnios or Turkish Bath Houses drawing regular visitors. But those facilities served a single purpose — bathing — and they were heated enough to work up a serious sweat, which wasn't exactly appealing when temperatures outside were already climbing. That all changed in 1742, when The Daily Advertiser ran an announcement that read, "This day is opened, at the Bagnio in Lemon Street, Goodman's Fields: The Pleasure or Swimming Bath, which is more than forty-three feet in length."
The Bagnio actually featured not one but two pools. For those desperate to escape the heat, one was kept chilled. The other was maintained at a warm temperature, perfect for soothing aching muscles or taking the edge off during the colder months. Both pools had their water refreshed daily, making them far cleaner than the city's rivers. Of course, there was a catch — a subscription cost a guinea, which effectively meant only London's wealthier residents could afford to take the plunge.