The UK's first natural geothermal lido has opened - and it rivals the Iceland's famous Blue Lagoon.The sustainable spa, filled with natural salt water is located at the iconic art deco Jubilee Pool in Penzance and uses entirely natural methods to keep its waters at an balmy 35°C all year round.The highly anticipated pool also boasts amazing views out to sea, offering the perfect place to relax in the warm waters watching the world go by.It opened to the first wave of swimmers on September 1,