Andy Sands / Blackbird (Turdus merula) female collecting mud from garden flower pot for nest building, Hertfordshire, England, March

Michele Westmorland / Himba people, close up of tradtional wooden and mud hut with cooking pot, Skeleton Coast, Namibia

Theo Allofs / Mud pot, Waiotapu thermal area, New Zealand

Igor Shpilenok / Mud pot with boiling clay, Uzon Caldera, Kronotsky Zapovednik Reserve, Russia.

Igor Shpilenok / Boiling red clay mud pot, caused by underground volcanic activity, Valley of the Geysers, Kronotsky Zapovednik Reserve, Russia.

Igor Shpilenok / Mud pot with boiling clay, Uzon Caldera, Kronotsky Zapovednik Reserve, Russia.

Tui De Roy / Volcanic mud pots, fine graphite mud boiling at high temperatures, Rotorua, New Zealand