"Duluth Love Locks" ~ Apparently Duluth has its own version of Love Locks...
In recent months, similar locks have been removed from bridges in Paris, Rome, and elsewhere due to structural problems caused by the cumulative weight (45 tons in one case!). According to BBC News, "The custom is inspired by a book by novelist Federico Moccia in which a couple place a bicycle lock around a lamppost and throw the key into the Tiber. The gesture was meant to symbolise the couple eternally locking their hearts together."
(P.S. If you love Duluth, purchase this photo or take a selfie here; please don't leave a lock. Leave no trace.)