This was my third trip to Tromsø, which is all the way at the top of Norway. I had seen the Northern Lights a few times in the past (e.g., see here), but this was by far the best display. After waiting in the freezing cold for over an hour without any lights at all, things eventually got going. It started out pretty usual: the sky became full of green lights that were slowly moving around, fading in and fading out. That was pretty cool, and I was having a great time getting a ton of photos. But then around midnight, it all changed: a solar flare hit the atmosphere and the sky lit up in an amazing light show. The green sloth-like lights were suddenly replaced with shimmering curtains of red, green, white, and purple flashes. It was absolutely mind-blowing!