More than 600 runners and walkers took part in the annual Willow 10K at historic Hatfield House on Sunday.
Back for its 11th year, the family event raises funds for Welwyn Garden City-based charity Willow, which is marking its 20th anniversary.
Willow is the only national charity working with seriously ill young adults aged 16 to 40 to fulfil uplifting and unforgettable 'Special Days'.
Hatfield House's Lady Salisbury officially started the race alongside Willow's co-founders, Bob and Megs Wilson.
Former Arsenal goalkeeper Bob said: "We love this event, seeing the same faces return with a smile each year along with new runners and charity supporters joining every time, many of whom have a moving story as to why they are taking part or supporting Willow.
"It's such a fun and friendly event which raises invaluable funds for Willow Special Days, which provide much-needed hope and happiness."
As well as the main 10K, the day included a 1K junior race and a shorter 5K route.
The weather held and competitors stayed dry around the scenic course, which includes areas not normally open to the public.
Hertfordshire resident Lizzie Erian shared her story about her own Willow Special Day following a diagnosis with Stage 4 oral cancer in January 2018, aged just 30.
Following surgery to remove half her upper jaw, and being told she may not be able to speak properly again, Lizzie has made a fantastic recovery and spoke articulately to the 10K participants.
She explained how the anticipation of her Special Day kept her motivated during treatment, and described the day itself as a "light at the end of a long dark tunnel".
Lizzie went on to run the 5K race, scooping a trophy as one of the top three finishers.
All participants were awarded a new wooden medal and finishers' T-shirt, sponsored by Simmons Bakers and Wrights Estate Agency.
Since 2009, the Willow 10K has raised more than £385,000, with funds raised for 2019 not yet confirmed as sponsorship is still coming in.
Organisers are already planning next year's running festival a half marathon route new for 2020.
Sign up for all routes - Junior 1K, 5K, 10K and half marathon - at willowfoundation.org.uk/RunWithWillow
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