Gentoo penguins near Danco Island, Antarctica (© David Merron/Getty Images)

Ruins of the ancient Maya city of Calakmul surrounded by jungle in Campeche, Mexico (© Alfredo Matus/Shutterstock)

'I Have a Dream' inscription at the location of Dr. Martin Luther King Jr.'s speech on the steps of the Lincoln Memorial in Washington, DC (© Pgiam/Getty Images)

Agoyán waterfall near Baños de Agua Santa, Ecuador (© Laura BC/Getty Images)

Glass igloos at the Kakslauttanen Arctic Resort in Saariselkä, Finland (© Lingxiao Xie/Getty Images)

Château de Beynac overlooking the Dordogne Valley in France (© Gareth Kirkland/Alamy)

Beach huts covered in snow in Brighton and Hove, England (© Tim Jones/Alamy)