The 51st parallel north is a circle of latitude that is 51 degrees north of the Earth's equatorial plane. It crosses Europe, Asia, the Pacific Ocean, North America, and the Atlantic Ocean.
At this latitude the sun is visible for 16 hours, 33 minutes during the summer solstice and 7 hours, 55 minutes during the winter solstice.[1]
Capital cities between the 51st and 52nd parallels are London and Astana.