The Wailing Wall is the most sacred site of Judaism, but everyone can go there. It is the retaining wall built by Herod two thousand years ago during the renovation of the Second Temple of Jerusalem. Also called the Western Wall or, in Hebrew, Kotel, anyone can get a few inches closer and insert a note containing a prayer between the cracks in the large stones. The important thing is that men and women access it from different sides (men on the left and women on the right).
