At the northern hemisphere summer solstice the Sun reaches it's furthest point north in the sky and the north pole is angled in line with the Sun and towards it. In Britain and northern Europe we have long hours of daylight and short night with the Sun high above the horizon at noon.
At the north pole at any time of year the stars (including those of the northern zodiac) turn round the north star but never rise or set. The summer Sun does not set either, and does not disappear until autumn when it moves into the southern sky.
A: At the summer solstice on the Arctic circle (23.4 degrees north) the Sun just grazes the horizon at midnight, but never fully sets and it is daylight for 24 hours.
B: South of the Arctic circle the Sun sets and the further south you go, the longer the time the Sun is below the horizon at night. In the UK the Sun is never far below the northern horizon and we experience twilight extending through the night.
The noon time Sun gets higher in the sky the further south you go. The height of the midday Sun on the summer solstice depends on your location. In Scotland it is around 56 degrees above the horizon, in the southern UK it can reach 62 degrees.
At the same time it is the winter solstice in the southern hemisphere and the situation is opposite to that in the north.