protests over gas? well, they lasted weeks because the dweebs that drive the gas refused to do so. So, really it only took a handful of people to hault the distribution.
The police say 150,000 and I don't know what pics you saw but look at the pic on the top of this article:
http://news.bbc.co.uk/1/hi/uk_politics/2285861.stm
So, i would suggest you didn't see the whole thing. The march, from what I read, took place from Embakement (where that pic is) to Parliment. Not really a big park along that route so I would think that the CNN person might have been in a park where people were gathering together to go to the main march.
Just for FYI..I don't have a clear cut view on this myself other than being rather uneasy about it but I'm not going to deny it was a big turn out.
Though, have a look at a british newspaper on May Day and see what London looks like then.
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