Blue Lagoon, Grindavík, Iceland

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In hot water. Blue Lagoon spa, Grindavík, Iceland

Let's be frank here, the origin of today's beautiful picture is a pool of wastewater from a nearby geothermal plant. While it may not sound enticing, Iceland's Blue Lagoon is one of the country's most-visited attractions. The trick is to not get stuck on the 'waste' part of wastewater. The water here is clean, always hovers around 38°C, and is enriched with tonnes of silica - which is what makes it blue - and sulphur thanks to the plant's processes. Those minerals, along with a little algae, are believed by some to combine to become a highly beneficial tonic for skin and overall well-being.