Spending a calm winter night under an Arctic sky lit up by the Northern Lights is an often-cited 'bucket-list' experience and among the reasons more people are visiting northern Iceland. The remote region at the edge of the Arctic Circle is one of the best places in the world to spot the colorful phenomenon. The aurora borealis, or Northern Lights, occur when a magnetic solar wind slams into the Earth's magnetic field and causes atoms in the upper atmosphere to glow. The lights appear quite suddenly and the intensity varies - the most amazing are bright green with purple and yellow at the base. Sightings depend on a mix of luck and effort. Traveling away from city lights is most often necessary - that has led some driver to take hazardous mountain roads. But many foreign visitors lack the experience and expertise to handle Iceland's wintry road conditions, and police are increasingly worried about them being distracted and unprepared. Some get into accidents because they are scanning the sky for the rare Northern Lights, not the road, which may be icy, bendy, or both.