In the northern hemisphere it is 21 June.
June 21st is Midsummers day and Stonehenge was aligned so that at dawn on Midsummers day the first rays of sunlight pass between the uprights and hit the altar stone.
24 June in most countries.Some begin celebrating on 23 June.See link below for full details.
Who_is_Titania_from_a_midsummer_night's_dream
midsummers nightdream
Lysander & Hermia
Comedy
William Shakespeare.
Absolutely nothing ! Pagans celebrated midsummers day, and the winter solstice long before religion became widespread. Many so-called religious festivals have their origins in pagan rituals.
Hermia.
the woods
That depends on your latitude. You can look up the times of sunrise and sunset for any location on the U.S. Naval Observatory's web site at the link below.