A man wearing flannel and blue jeans stands next to a solo tree in an old lava field, Oregon, United States of America, North America

Hiker on the access path to Tsakhats Kar Monastery with the Smbataberd fortress in the background, near Yeghegnadzor, Vayots Dzor province, Armenia, Eurasia

A walker above Ullswater in the Lake District, Cumbria, England, United Kingdom, Europe

Fields of lavender in full bloom under a full moon in the Valensole plateau with mature tree standing solo.

Fields of lavender in bloom at sunrise in the Valensole plateau with mature tree standing solo.

Fields of lavender in full bloom under a full moon in the Valensole plateau with mature tree standing solo.

Time lapse photo of solo hiker in Grand Teton National Park

Solo hiker in Grand Teton National Park passing trail sign

A backpacker observes the midnight sun peeking through the clouds from an unnamed fork of the Atigun River still partially covered in aufeis (sheet-like ice formations) in a remote valley of the Brooks Range, Alaska, United States of America

Woman hiking along the Dempster Highway enjoying the scenery, and standing on a piece of late season ice along the Klondike River in Tombstone Territorial Park; Yukon, Canada

Hiker contemplating the Lac du Lauvitel (1530 m) on the GR 54 long-distance hiking trail, Tour de l'Oisans et des Ecrins, Veneon valley, Ecrins National Park, Isere, France

Walker walking on a green stream following an old abandoned railway line connecting Beauvais to Amiens - in autumn, Picardy, France.

Vallee de la Claree, Kuepfer's Buttercup (Ranunculus kuepferi) bed and hiker on the GR57, Nevache, Hautes-Alpes, France

Split image of guide with snowmobile waiting the divers, only in springtime, when the hard winter slowly subsides, are the ice-cold waters suitable for divers who can dive around a iceberg that floats in crystal-clear water, Tasiilaq, East Greenland

Hiker on the suspended footbridge of Spasimata on the GR 20, Cirque de Bonifatu, Corsica Regional Nature Park, Balagne, Corse-du-Sud, France

Hike to Lac Palluel (2472 m) from the hamlet of Dormillouse, Freissinieres, Ecrins National Park, Hautes-Alpes, France

Walker walking on a green stream following an old abandoned railway line connecting Beauvais to Amiens - in autumn, Picardy, France.

Hiker on the suspended footbridge of Spasimata on the GR 20, Cirque de Bonifatu, Corsica Regional Nature Park, Balagne, Corse-du-Sud, France

Snowshoeing at La Dole, Jura sur Leman ski resort, Canton Vaud, Switzerland

Hiker on the Tours du Lac, Lake Allos (2226 m) and in the background Mont Pelat (3051m), Haut-Verdon, Mercantour National Park, Alps, France

Woman on top of a mountain, view on Lake Wakatipu with city of Queenstown, Remarkables mountain range, South Island, New Zealand

The Hautes Combes, Nordic skiing, in the background: the Jura Mountains, Jura, France

The Hautes Combes, Snowshoeing, in the background: the Jura Mountains, Jura, France

Mount Pelvoux (3932m) and the Pelvoux glacier illuminated by a full moon night, hiker at the Glacier Blanc refuge (2580m), Vallouise valley, Brian?onnais region, Ecrins National Park, Hautes-Alpes, France

The Hautes Combes, Snowshoeing, Jura, France

Installation of a sign on a hiking trail indicating the presence of nets to capture bats as part of a pollination study, rainforest of the "La Selva" research station in Puerto Viejo de Sarapiqui, Costa Ricardo

A tourist hiking in Neko Harbour, Antarctica.