What's the best way for an airline to celebrate the one-year anniversary of offering ultra-low fares to Iceland? Naturally, the answer is to offer more ultra-low fares to Iceland. Wow Air, which Condé Nast Traveler recently ranked at one of the cheapest ways to get to Europe, has launched a 24-hour sale, with $99 one-way airfares between the U.S. and Iceland.

Fly from Boston or Washington, D.C.–Baltimore to Reykjavik this winter and experience the Northern Lights, hike to frozen waterfalls and steaming volcanic lava fields, and soak in the famous Blue Lagoon thermal spa when the early nighttime falls. For a little more inspiration, check out our guide to LGBT-friendly Reykjavik and how to spend a perfect weekend both in and out of town.

Of course, with any nearly unbelievable fare deal, there is good news and bad news. The good news is that the dates of travel are completely open, though the lowest fares are found for travel this winter, from November through March. The bad news is that Wow levies a range of extra fees to keep the ticket price low, and traveling over winter will mean packing more warm garb and paying more baggage fees. But, even with that additional cost, this sale remains the most affordable way to view Iceland's aurora borealis at the end of its 11-year solar cycle of maximum brightness—the lights won't be as dazzling again for a decade.

Book this deal on Wow Air's U.S. website by the end of today.