With a heart as big as the Boston Skyline, Spencer earned worldwide admiration as the beloved Boston Marathon dog. For eight years, the golden retriever cheered for thousands of runners in the cold, freezing rain, and even as he recovered from cancer.A therapy dog who lived in Holliston, Mass., Spencer began rooting for Boston Marathon runners in 2015, two years after the bombing that injured hundreds and killed three people.Every Patriot's Day at Mile 3 of the race, Spencer sat on the side of the road holding his Boston Strong flag, inspiring athletes and fans to be brave and to never give up."He was like a little angel," his dad said.A symbol of hope and inspiration to cancer survivors and runners, Spencer was honored as the official dog of the 126th Boston Marathon in 2022. He grew so famous that runners lined up to take photographs with him. They gave up precious race time, so they could hug and pet the marathon's cherished fan. Not long after Spencer celebrated his 13th birthday, doctors diagnosed him with his second bout of cancer, and he died in February 2023.A few months later as the 127th Boston Marathon began, runners said they still felt Spencer's spirit at Mile 3 of the race route."We will never forget him," they promised.A story of hope, inspiration, and a dog who lit up the world with his love.