Many of the UK's lidos date back to the 1930s, but Lymington Sea Water Baths goes all the way back to 1833. The 110-metre open-air sea water bath is the oldest in the UK, and is also one of the largest of its kind. It's home to 200 metres of inflatable obstacle courses, stand up paddle boards, and aqua jousting. There's also a children's splash pool and a kiosk/cafe.