NORTHERN Ireland's biggest mass participation photographic event is back.
For your chance to win a 'staycation break' we're asking you to take a photograph that illustrates best what Northern Ireland means to you.
The unique aspect of this competition is that all photographs have to be taken on just one day this summer – Saturday, June 29.
Belfast Telegraph picture editor Gerry Fitzgerald said One Summer's Day has captured the "hearts and imaginations" of many people throughout Northern Ireland over the last three years.
"The idea behind the competition is that as many people as possible across the country go out on June 29 and take a photograph of somewhere in Northern Ireland that is important to them," he added.
"It may involve people or pets, it may be an action shot, or it may just be a beautiful scenic photograph.
"It's really up to the individual photographer."
As well as the chance to win a short break, the top 100 photographs will be included in a special commemorative supplement which will be produced and distributed inside the Belfast Telegraph in September.
Closing date for competition entries is Saturday, July 13, with winners to be announced in September.
In the run-up to One Summer's Day on June 29, the Telegraph and NITB are asking readers to tell us where in Northern Ireland you would like to photograph and why.
Send your answer with a photo of yourself in an email to one summersday@belfasttelegraph. co.uk