Neil Lewis from Cardiff was among the Welsh people who ran the Boston Marathon.
His wife and 20-week-old baby daughter were at the finishing line just an hour before the explosions, and he told us about his relief they didn't go back out to watch other people finish.
He was speaking to us by phone from Boston, describing the city as "eerily quiet", the morning after the explosions.
At least three people died in two blasts near the marathon finishing line.
You may find some of the images in this video upsetting.