Sven Zacek / Ural owl (Strix uralensis) perched in tree sleeping, viewed through a fence, Estonia.

Sue Flood / Aerial view of sand dunes near the Skeleton Coast, Namibia

Heather Angel / Snake's head fritillary (Fritillaria meleagris), view into flower with linear green nectaries. In cultivation, Surrey, England, UK. April.

Ashley Cooper / Stone stripes on Coniston Old Man in the Lake district, UK. These patterned ground features are caused by freeze thaw cycles which heaves the larger stones into lines down slope. January 2012

MYN / Andrew Snyder / Close up of Paper wasps (Mischocyttarus sp.) constructing a linear nest, Kanuku Mountains, Guyana, July. Meetyourneighbours.net project.

MYN / Andrew Snyder / Paper wasps (Mischocyttarus sp.) constructing a long linear nest, Kanuku Mountains, Guyana, July. Meetyourneighbours.net project.

Simon Colmer / Puss Moth (Cerula vinula) linear life cycle showing egg, larva / caterpillar, pupa / chrysalis and adult moth. Digital composite.

Pete Oxford / Aerial view of linear sand dunes and river, Skeleton coast Namibia

Pete Oxford / Aerial view of linear sand dunes. Skeleton coast Namibia

David Gallan / Dead trees continuing to burn after a bushfire has swept through a forest, Biamanga National Park, New South Wales, Australia, December 2019.

David Gallan / Slow motion clip of dead trees continuing to burn after a bushfire has swept through a forest, Biamanga National Park, New South Wales, Australia, December 2019.

David Gallan / Close-up of a dead tree continuing to burn after a bushfire has swept through a forest, Biamanga National Park, New South Wales, Australia, December 2019.