Two million people to attend an event is clearly not safe.
I remember being at Macy's thanksgiving parade a couple of years ago when they have upwards of three million people attending, and that was complete and utter chaos.
Unfortunately you can't have any real crowd control when there's that many people in a small area.
the logistics of trying to organise an event with that many people must be horrendous and with the best will I can't see how people wont get hurt or injured
I've been to a few music festivals with only a small fraction of those numbers and I've seen the chaos that can ensue when there's a crowd surge with only a few 1000 folk. can't imagine what it is like multiplied a 1000 fold!