Christopher was inspired to take pictures of locals like Jessica, below, while getting a tattoo himself.
Soon he was back at the tattoo parlour.
Later that week, he mentioned it to his friends at the Boston Center for Adult Education, where he's an instructor.
He's now taken pictures of close to 80 people.
It's given him tremendous insight into what happened that day.
He's received support from the whole New England business community.
The book will raise money for charity.
He feels overwhelmed by the response.