I had heard of the 'Love Locks' trend, where couples put a padlock symbolizing their love for each other in a public place. Often they carve their names in the lock as well. Once the locks are in place they throw away the kiey. All over the world, there are hot spots for these things, with hundreds or thousands in one area. I hadn't seen it in person until we visited the Great Wall. It looks like it's a fairly new idea here, but there were still hundreds of them linked to a chain at the base of the wall section we climbed.