she remembers david telling her about this place before they came here , about how lovers would secure the padlocks and throw the keys into the seine as a mark of their enduring love , and of how when the padlocks were painstakingly removed by the city authorities they simply reappeared within days , engraved with everlasting love , the initials of lovers who , two years on , might still be together or might by now have moved to different continents rather than breathe the same air .