Paris, Rome, and Dublin have all famously done it.
But Belfast has also been quietly acquiring its own bridge of love.
'Love locks' - padlocks attached to fencing, have been accumulating on a footbridge over the river Lagan, in the heart of the city.
Around 30 locks adorn the bridge beside the Lagan Lookout as declarations of love.
Some just have names, others messages and dates painted on.
The Pont des Arts in Paris is the best known location for these padlocks but the craze has spread across the globe.
It is thought the idea was sparked by a book by Italian novelist Federico Moccia
He wrote about a couple who placed a bicycle lock around a lamppost and threw their key into the Tiber river.
The gesture was meant to symbolise the couple eternally locking their hearts together.
One couple arriving to place a lock on the bridge in Belfast for the first time said it was "a nice reminder" every time they would have to walk past it.
They had only been going out for a month but were sure the gesture represented something very important.
"It's forever binding. You can't come back a few years later and take it off".
But not everybody sees it through such romantic-tinted glasses.
"It's a bit odd" one passer-by said.
"I'm too old for doing this, and I really don't think my husband would be interested if I suggested such a thing."
Another passer-by said he was more likely to throw his wife over the bridge. He assured me he was joking.
But one young couple who spotted their friends' names on the fencing said it was a romantic gesture that they would consider.
"We would probably write our names and the date we started going with each other, 18 July 2009".
Officialdom has a different view of the practice.
The mayor of Rome, in 2007, introduced a 50 euros (£43) fine for attaching padlocks to the Ponte Milvio bridge.
In 2012, Rome city council removed thousands of 'love locks' with bolt-cutters from the bridge, arguing that they were damaging its ancient structure.
Dublin City Council removed locks from the Ha'penny Bridge in the city centre for similar reasons.