The highest UV index ever recorded was an extraordinary 43.3, measured on December 29, 2003, at the Licancabur volcano in Bolivia. This record-breaking UV level is far above typical Earth surface values and is comparable to radiation levels on Mars. The extreme UV index resulted from a combination of intense tropical sun, high elevation (the volcano is about 19,423 feet or 5,920 meters high), and unusually low ozone levels at that time
