The Norwegian Trekking Association`s collection from Claus Helberg constitute the largest part of the collections at the mountain museum. The collection includes, among other, archives and artefacts from the very first mountain tourism and the former DNT (Norwegian Trekking Association). Here you`ll find patent accountants, alienated books and donations to DNT. In the collection we also have over a thousand photographs from the mountains and mountain tourism from the end of the 1800-century up until 1960. The diaries, sketches and photografs of William Cecil Slingsby is a valuable part of the collection.