A recent article in NRC Handelsblad's English section: "So many bikes, so little space." It discusses incredible statistics on the number of bikes in the Netherlands, particularly the problem at major train stations:

Last year alone, Utrecht removed 9,000 bikes, almost twice as many as the year before. In Nijmegen, the numbers went up from 5,474 to 6,331 in 2009. In the same year, The Hague took 7,141 of its citizens' bicycles off the street, nearly 2,000 more than in 2008. Rotterdam was the only major city where the number removed remained stable at 12,000. Amsterdam, however, is in a league of its own. Last year, 45,000 bicycles were removed there, 6,000 more than in 2008.

The article mentions the problems of "orphaned" bicycles, and taught me about a number of interesting methods used to deal with these forgotten two-wheeled friends:

Bicycle removal teams have developed a special method to determine whether a bike has been abandoned: they put little stickers on a pre-determined position on the bicycle's wheels. If they return and the stickers are no longer in the same place, this means the wheel has turned and the bike has been used. If it hasn't, the civil servants put a large orange sticker on the bike announcing it will be removed by the city if the owner does not do so himself within a month.

It's great reading, and a good education into what happens to all that metal piled up in every Dutch city.