The Midnight Sun is just that — when the sun is visible at 12 am. Head north of the Arctic Circle at the height of summer and you’ll find yourself in its constant golden glow, 24/7. The magic latitude is 66 degrees 33' N, cutting through the northernmost countries on the globe, including Iceland, Sweden, Finland, Russia, and Norway, known as the Land of the Midnight Sun.

The optimal time to see the natural phenomenon is from June 21 to July 1. The Midnight Sun lasts longer the further north you go, though. For example, in the Norwegian archipelago of Svalbard, more than 500 miles north of mainland Norway, the Midnight Sun shines from April 20 to August 22.

Choose a Baltic itinerary, and be sure that the itinerary includes towns above the Arctic Circle, such as Tromsø or Kirkenes. Norwegian line Hurtigruten has cruises to northern points like Svalbard and along the country’s coast from Kirkenes to Bergen, while Viking Ocean Cruises does “Into the Midnight Sun” cruises from Bergen to Greenwich. In June, Royal Caribbean's Serenade of the Seas cruises out of Copenhagen in June and up above the Arctic Circle, and Windstar's Star Legend does an 11-day "Lands of the Midnight Sun" cruise out of Dublin that includes ports in Norway before cruising across the North Sea to Reykjavik, Iceland. You can also see the Midnight Sun with Holland America's new Koningsdam, which cruises out of Amsterdam in July for a trip up the Norwegian coast to Honningsvag — the northernmost city in Norway. 

Surreal. That’s probably the best word to describe your first glimpse of sun at a time when you should be sleeping. And combined with a healthy dose of jet lag, you may feel a little loopy. It might sound counterintuitive to wear your sunglasses at night (unless you’re Corey Hart), but you’re going to need a good pair of shades. Your eyes may be sensitive to the constant brightness. And, while the curtains on ships in this region are generally excellent, light sleepers should pack an eye mask.

When you do finally convince yourself to get some shut-eye, it will feel like you’re going down for a short snooze versus a full night’s sleep. You can kiss your Circadian rhythm goodbye (you know, your body’s internal clock that senses when it’s time to wake up and when it’s time to go to sleep). While you probably won’t completely adjust by the end of your trip, the prospect of going to bed while the sun is up does get easier after a few days.

The constant light is an invitation to explore, meaning you’ll find yourself up later than you should be to, say, attend a midnight concert in Tromsø's Arctic Cathedral. For the people who live in this corner of the world, the Midnight Sun is an opportunity to get outside and enjoy nature (remember, it’s completely dark here for two months in the winter, and very cold). So it’s the perfect time of year for a hike along a glacier or a kayaking trip.