Answer:
Solstice. The Solstice also occurs twice a year, we have a summer solstice around the 21 June in the Northern Hemisphere and a winter solstice around the 21 December. The summer solstice is the day when the Northern hemisphere experiences its longest period of daylight all year.
That year's summer solstice was the longest period of daylight the Northern Hemisphere has ever seen (and, conversely, the 1912 winter solstice was the longest night we've ever seen)
