This is a bridge in Paris. You hang locks on it with the name of you & your boyfriend/girlfriend/best-friend then throw the key into the river. So even though the friend/relationship may end, you can’t remove the lock. It stays there forever
Attach a lock onto the Pont des Arts Love Locks pedestrian bridge in Paris, walking distance from the Louvre. Write you and your loves name on the lock and throw the key in the river. Would love to do this some day when I go to Paris!