Synchronous fireflies illuminate the forests of Great Smoky Mountains National Park, USA (© Floris van Breugel/Minden Pictures)

Sunwapta Falls in Jasper National Park, Canada (© Schroptschop/Getty Images)

Two mountain bike riders make their way down the Shafer Trail switchbacks on White Rim Road in Canyonlands National Park, Utah, USA (© Grant Ordelheide/Tandem Stills + Motion)

Mountain bikers on White Rim Road in Canyonlands National Park, Utah (© Grant Ordelheide/Tandem Stills + Motion)

Walter's Wiggles trail in Zion National Park, Utah, USA (© Dennis Frates/Alamy)

La Pertusa教堂，西班牙莱里达 (© bbsferrari/Getty Images)

Hermitage of La Pertusa, Lleida province, Spain (© bbsferrari/Getty Images)

Galápagos sea lion off the shore of Fernandina Island, Galápagos Islands, Ecuador (© Tui De Roy/Minden Pictures)

Baron Lake and Upper Baron Lake in the Sawtooth Wilderness in Idaho (© Patrick Brandenburg/Tandem Stills + Motion)

Griboyedov Canal and the Church of the Savior on Spilled Blood in Saint Petersburg, Russia (© Tomas Sereda/Getty Images)

Olive trees and poppies in Luberon Regional Nature Park, France (© Hemis/Alamy)

The Dourbie Gorge Corps Mill and adjoining bridge in Grands Causses Natural Regional Park, France (© Hemis/Alamy)

Spotted Owlet in Bharatpur, India (© Bernard Castelein/Minden Pictures)

Surfer walking between palm trees in Medewi, Bali, Indonesia (© helivideo/GettyImages)

Surfer on the beach in Medewi, Bali, Indonesia (© helivideo/Getty Images)

Eibsee lake at the base of Zugspitze mountain, Bavaria, Germany (© Marc Hohenleitner/Huber/eStock Photo)

Jabiru storks in the Pantanal of Brazil (© Juan-Carlos Munoz/Minden Pictures)

Midsummer light captured at a lake near the city of Örebro, Sweden (© Anders Jorulf/Getty Images)

Artist Saype's 'Beyond Walls' installation in the Parc de la Grange, Geneva, Switzerland (© Valentin Flauraud/Shutterstock)

Pyramid Lake in Jasper National Park, Alberta, Canada (© Peter Adams Photography Ltd/Alamy Stock Photo)

Akbar's tomb at Sikandra near Agra (© Howard Mitchell/Getty Images)

Bull Point in Devon, England (© Robert Harding World Imagery/Offset by Shutterstock)

Bull Point in Devon, England (© Robert Harding World Imagery/Offset by Shutterstock)

German Navy tall ship Gorch Fock in waters close to Reykjavík, Iceland (© DEEPOL by plainpicture/Henn Photography)

German navy tall ship Gorch Fock in waters close to Reykjavík, Iceland (© DEEPOL by plainpicture/Henn Photography)

Grandidier's baobab forest near Morondava, Madagascar (© Thomas Marent/Minden Pictures)

The Empire State Building lit up in honour of Pride Weekend in 2014, New York City, USA (© C. Taylor Crothers/Offset by Shutterstock)

Goats in an argan tree near Essaouira, Morocco (© Nizz/Shutterstock)

Lavender field at Hinode Farm, Kamifurano, Hokkaido, Japan (© DoctorEgg/Getty Images)

Jungle cat hunting somewhere in India (© Lila/Alamy)