In Iceland, the Arctic Circle is best treated as a natural-light and latitude concept that becomes practical only when you plan around Grímsey.
The Arctic Circle is a line of latitude, not a gate, viewpoint, or visitor center. It marks the southern edge of the area where the sun can stay above or below the horizon for at least one full day each year, depending on the season.
That makes it meaningful, but it also makes it easy to over-plan. In Iceland, the useful traveler question is not whether the Arctic Circle is famous. It is whether you have enough time, weather margin, and interest to reach Grímsey, the North Iceland island where the line gives visitors a concrete place to walk to.