Linked from
The 16 pages that link to Midnight sun, each with the reason it gives.
Arctic CircleRelated: North of the circle, summer brings at least one day with no sunset.
Antarctic CircleRelated: It occurs south of the circle during the austral summer.
June solsticeRelated: It occurs north of the Arctic Circle around the June solstice.
LongyearbyenRelated: Long summer daylight contrasts with Longyearbyen’s dark winter season.
Northern EuropeRelated: It marks the region's far-northern seasonal light conditions.