Estimated crowd around 100,000...
It is a complex phenomenon:
* A deliberate "Bread and Circuses" policy to keep the people quite, while they are being systematically looted.
* An outlet for the manic-depressive Israeli, who are into partying, particularly in Tel Aviv, as long as the security situation is OK. But the mood can change to depression in a minute, with deterioration of security conditions.
* Part of a bit sleazy, but successful enterprise of the Tel Aviv Municipality to brand Tel Aviv as a global party city. Lonely Planet listed Tel Aviv a couple of years ago one of the top three party cities in the world...