On June 21st the summer solstice is celebrated, that is the official start of the astronomical summer and the day is the longer of  the year in its light hours.
During this day  the sun reaches the point of maximum height in the sky.

In countries like Iceland, Norway and Sweden, on the day of the summer solstice, there can be up to 20 hours of light. In particular, in Norway, in the northern part near the Arctic polar circle, there is a phenomenon called “midnight sun”.

Practically the sun sets on the horizon like going down, but then has a “rebound effect” thus returning in the sky.

In England, at the Neolithic site of the monoliths of Stonehenge, a monolith is placed at the center of a circle of stones that is completely illuminated only on this day, it is clear that those who placed it in that particular position had a thorough knowledge of the  astronomy.

Last curiosity: the summer solstice with the greatest number of hours of light that our planet has ever had was in 1912.

This year we will welcome the summer with its solstice at 10:07 am.