Classic mountain marathons are usually a two day mountain / fell running event, with a strong orienteering element. Competitors usually participate in teams of two, and have to carry their own food and tent. There are various classes of event falling under two main categories:
Linear Course - straight line courses, essentially a time trial where the fastest team around a set number of checkpoints over the 2 days wins.
Score course - Points based option where the team that collects the most points across the 2 days wins.