The Western Wall is Judaism's most holy site, as for centuries people have been going there to bewail the loss of the temple in 70AD. The Wall is not part of the temple itself, rather a continuation of Herod the Great's retaining structure that holds in the arches known as Solomon's stables (the huge dressed stones at its bottom date from that time), but this has not stopped its Sanctification and the practise of writing prayers on pieces of paper that are placed in cracks in the wall in the belief that God will take more heed of them.
The wall has been a subject of some controversy since the British Mandate period. The muslims have always claimed it as an integral part of their whole Sanctuary (Al Haram es-Sharif) and the place where Mohammed tied the winged steed that had brought him from Mecca (Al Buraq) while he experienced his "Night Journey", and the mandate authorities tended to side with them as being the larger part of the populace. During that time the only access to the wall was down a narrow alleyway at the back of the houses of the Mughrabi (Moorish) quarter, and this led to the blowing of the shofar being declared illegal as it "disturbed the residents". The residents did some disturbing of their own by driving flocks and herds through the alley even during Jewish High Holidays, and it was this antagonism tinged with the overwhelming relief of victory and being able to pray at the Wall without restriction that caused the Israeli government of 1967 to bulldoze the entire area to make way for the plaza that exists today, leaving over a thousand homeless.
Since then the Wall has become a symbol of national unity, with army swearing-in ceremonies taking place there regularly, but this symbol has weakened in recent years as the Orthodox attempt to monopolise its use even to the point of scuffling with Reformers and Conservatives over the issue of segregated congregations.