Thousands paid tribute to Princess Diana on her birthday.
A day before her birthday, Diana's brother shared a picture from the Diana Process of Wales Memorial Walk in London.
Spencer said he found himself "unintentionally on this walk today."
Diana's brother says memorial walk evokes poignant memories
"Strong" is the word, I guess - especially the day before Diana's birthday," he wrote.
Diana died in a car accident in Paris in 1996.