The first Bee Lady Day is marking the life of Jean Bishop, who won people's hearts by raising nearly £125,000 for Age UK in Hull.
Mrs Bishop, who died aged 99 in 2021, was often seen dressed in a bee outfit raising money on the city streets.
She was awarded a British Empire Medal in 2017 for services to charity and picked up a Pride of Britain award, which was presented by actor David Walliams dressed in a bee outfit.
Age UK said the day aimed "to inspire a brand new generation of fundraisers".
The day will be held each year on 13 May, which was Mrs Bishop's birthday.
More than 13,000 schoolchildren have been dressing as bees as part of the fundraising activities.
A ceremony at Hull railway station honoured older fundraisers with the Jean Bishop Legacy Award.
Winners are being taken to Doncaster for afternoon tea.
Buildings across the city, including Hull Minster, are being lit up in amber to resemble bees.
Age UK Hull & East Yorkshire fundraising co-ordinator Kayleigh Carter said the day was about "honouring and remembering the life and legacy" of Mrs Bishop.
"The work that she did helped thousands and thousands of people who use our charity," she said.
"Jean was a real advocate for older people.
"We're trying encourage to people to see how they can raise money for Age UK, but also the charity sector in general."
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