The ultraviolet index (UVI) is a measure of the level of UV radiation. UVI 3 is the level above which sun protection is recommended by the World Health Organization (WHO). But some of the most popular vacation destinations on the planet regularly experience a UVI of anywhere between 8 and 11. This means anybody failing to cover up in such conditions runs the risk of damaging their health, not least by promoting the onset of skin cancer. But how do you interpret UVI, and where in the world are some of the worst travel hotspots?
Click through and discover the countries with the greatest UV levels.