"82 pictures of bicycles taken during 73 minutes on 9/12/06 in Amsterdam, Netherlands."
http://www.ski-epic.com/amsterdam_bicycles/
I came across this and didn't come up here so I thought some might enjoy looking at culture differences.
Seems they know better than cable locks too. Look at the section,
Spectacular Gigantic Unbreakable Security Chains.
But, no helmets?