Magnus Lundgren / Wild Wonders of China / Fish and mussel farm. Zhifu Island, Shandong Province. Bohai Sea, Yellow Sea, China. September 2017.

Eladio Fernandez / Track through forest in Sardinero, Siboney, Cuba.

Ashley Cooper / Cares Gorge, Picos de Europa, northern Spain. June 2005

Ashley Cooper / Cruise ship off Illulisat, Greenland, July 2008.

Kirkendall-Spring / Walkway with tourists along Akaka Falls, Akaka Falls State Park, Hawaii. December 2016.

Jouan Rius / Walkway over reedbeds, Camargue, France. February

Melvin Grey / Limpkin (Aramus guarauna) adult standing on walkway handrail. Wakodahatchee Wetlands, Florida, USA. March.

Ernie Janes / Board walk in Donana National Park, Almonte, Spain, October 2017.

Ernie Janes / Brown fur seal (Arctocephalus pusillus) hauled out on board walk in Cape Cross seal colony, Namibia

Michael Hutchinson / Treetop walkway, Kew Gardens, London, England, UK, April 2016.

Michael Hutchinson / Treetop walkway, Kew Gardens, London, England, UK, April 2016.

Michael Hutchinson / Treetop walkway, Kew Gardens, London, England, UK, April 2016.