Sandnessjøen is well known for two things: the poet Petter Dass and the mountain range De syv søstre (The Seven Sisters). The sharp mountain formations around Sandnessjøen and the Helgeland coast were shaped in the ice age, more than 20 000 years ago where the landscape surrounding De syv søstre was characterized by glaciers that dug into soft rock and transformed the landscape to the shiny peaks seen today.