Now, they ran over snowy hills and down into frozen valleys. They stopped only to rest and eat. They wanted to stay ahead of the other teams. The racers had to go a thousand miles across Alaska. Alaska is one of the coldest places on Earth. The dogs’ thick fur coats helped keep them warm in the cold wind and weather. In many places along the route, the snow was deep. Pieces of ice were as sharp as a knife. The ice could cut the dogs’ feet. To keep that from happening, Julie had put special booties on their feet.