If you're yet to take a dip in the unique surrounds of King's Cross Pond, you'd better get booking quick: the pond will close on 26 October, it has been confirmed.
The open air art project was only ever intended to be in place temporarily, but this news has still come as something of a cold-water shock.
King's Cross Pond opened on 22 May last year, and was planned to offer Londoners a special place to swim for 'at least two years'.
The early closure, after just 17 months, is being challenged by Londoners with a petition.
The change.org petition set up to save the pond says, "This swimming oasis in the urban centre of a world-class city, originally designed as a usable art installation, is a wonderful and popular asset for the local community and for visitors.
"The UK's first ever man-made fresh water public bathing pond has become one of London's best-loved amenities, bringing benefits to the area and beyond.
"Do not close and scrap it: instead keep it as a truly sustainable and green centre for the Kings Cross area. #savekxpond"
Argent King's Cross Ltd, the property developer responsible for King's Cross Pond, says the pond was only ever intended to last "two summers".
It has plans to turn the space into a park, with a new public artwork to replace the pond: a giant installation of 35,000 bicycle reflectors.
The company has also promised to re-home the wildlife and plants currently inhabiting the pond, and to recycle as much of the material used in the project as it possibly can.
We can't help thinking of those other 'temporary' installations that have become time-worn institutions and now mean so much to our city: the Cenotaph, the Young Vic, and the London Eye, for starters...