Tony Wu / Indo-Pacific bottlenose dolphin (Tursiops aduncus) leaping out of the surf, South Africa, Indian Ocean.

Jack Dykinga / Mesquite Dunes, with sand patterned ridges against the Amargosa Mountains in afternoon light. Death Valley National Park, California, USA, January.

Philippe Clement / Traditional Royal Mail red mailbox in the countryside at Coigach, Ross and Cromarty, Scottish Highlands, Scotland, UK, September 2016.

Kirkendall-Spring / Woman looking inside the mailbox on the summit of Mailbox Peak near North Bend, Washington, USA. March 2016. Model released.

Enrique Lopez-Tapia / Sign and box for volcano post, the only known post box on an active volcano. Mount Yasur, Tanna Island, Vanuatu, September 2008.

Sam Hobson / Fallow deer (Dama dama) beside bus stop and letterbox. London, UK. January.

Andy Trowbridge / Yellowhammer (Emberiza citrinella) perched on snow covered letterbox with outside house, with light in background. Southern Norway, December.

Aflo / Young boy sitting on wall, with Toy Poodle holding newspaper in mouth, next to letterbox

Aflo / Toy Poodle sitting on garden wall, holding newspaper in mouth, next to letterbox

Franco Banfi / Royal Mail post box inside the former British Base A, now a museum and post office at Port Lockroy, Goudier Island, Antarctic Peninsula, Antarctica.

Pal Hermansen / Mailbox beside bare trees. Akershus, Viken, Norway. April.

Pal Hermansen / Mailbox between bare trees. Akershus, Viken, Norway. April.

Doug Gimesy / Burnt out letter box on the Great Alpine Road which was burnt during the November / December 2019 fires. Great Alpine Road, Sarsfield, Victoria, Australia January, 2020. Editorial use only.