I love swimming and I love being outside. London is great if your into both these things. I swim at London Fields Lido which is heated all year round. Its best in the winter when the steam rises from the water and if your lucky its snowing a little on your head. If your brave you can also go for the unheated option of the Serpentine or Hampstead Ponds.
Need some clean air or just a time-out? Kew Gardens is a short train ride away from the city centre but is provides you with space, greenery and and a small holiday for the lungs. The garden contain tropical glasshouses and interesting architecture, so it is a treat for both body and mind.
Frank's bar opens on the roof of a multi-storey carpark in Peckham every summer. It's great to go for a drink and get this phenomenal view of London. I love the design of the bar, which is different each year, and the exhibitions are always interesting.