Just got back from it. And yeah, it is a boatload of people, but 500,000? Where did they all park? Doesn’t seem possible. If I had to guess, maybe 200,000, but I doubt even that.
And if you have never been to it, put it on your bucket list. It is definitely worth traveling here to go to. Forget Times Square on New Year’s Eve, this is a way better thing!
Your question probably can’t be answered yet, but a half-million people is a huge number and very hard to pack into even quite a large space. It can be identified based on computer imaging if any exists with high-angle shots over time.