Despite this city having some lovely outdoor swimming spots, it's still only the bravest among us who will tackle the icy depths of a London waterway, no matter the time of year. We're pretty sure, though, that people would be way more likely to take the plunge if we took a leaf out of Seattle's book and added floating saunas into the mix. The wa_sauna (or Washington Sauna, named after the US state in which it's based) launched on Seattle's Lake Union recently. Itís a compact wooden structure with its own wood-burning stove that can be manoeuvred through the water with the help of a small motor. It holds up to six people (sauna party!) and can be booked for two or three hours at a time. Sounds like the ideal way to take the 'brr' out of British summertime.