NORWAY. Alta. The dog-sled race in Alta, is said to be the toughest dog-sled race in the world. There are two classes of race; the 500km (with 8 dogs) and the 1000km (with 14 dogs). The entrants must ensure they have enough food for 5-6 days for the 1000km race around this northern part of Norway. Dogs are selected for their friendliness otherwise they lose too much energy bitching with one another. 2001.