[February, 2012] The custom that lovers swear their love, put the lock on the rail or fence and throw the key away started from an Italian romantic comedy film apparently.
I found one location in Monza, north Italy, too.
At first lots of locks on the rail was a puzzle for me, but now I heard that there are places like this in Japan, too, so it is not a surprise any more, but this photo is one of my collection.