View of Grand Canyon west of the historic Watch Tower, managed by the National Park Service, UNESCO World Heritage Site, Arizona, United States of America, North America

An interior view of the historic Desert View Watchtower at Grand Canyon South Rim, artwork created by Fred Kobotie in 1933, now owned by the National Park Service, Arizona, United States of America, North America

An interior view of the historic Desert View Watchtower at Grand Canyon South Rim, artwork created by Fred Kobotie in 1933, now owned by the National Park Service, UNESCO World Heritage Site, Arizona, United States of America, North America

Downward view from the third floor in the historic Desert View Watchtower at Grand Canyon South Rim, artwork created by Fred Kobotie in 1933, now owned by the National Park Service, UNESCO World Heritage Site, Arizona, United States of America, North America

Stairs up to the third floor in the historic Desert View Watchtower at Grand Canyon South Rim, artwork created by Fred Kobotie in 1933, now owned by the National Park Service, UNESCO World Heritage Site, Arizona, United States of America, North America

Downward view from the second floor in historic Desert View Watchtower at Grand Canyon South Rim, artwork created by Fred Kobotie in 1933, now owned by the National Park Service, UNESCO World Heritage Site, Arizona, United States of America, North America

Stairs up to the seconnd floor in the historic Desert View Watchtower at Grand Canyon South Rim, artwork created by Fred Kobotie in 1933, now owned by the National Park Service, UNESCO World Heritage Site, Arizona, United States of America, North America

Panorama of Tuzigoot and the Verde Valley, managed by the National Park Service, Arizona, United States of America, North America

A climber bouldering on the large granite boulders near Camp 4, the National Park Service campground underneath El Capitan, Yosemite Valley, California, United States of America, North America

Grand Canyon with the historic Watch Tower on the far left, managed by the National Park Service, Grand Canyon National Park, UNESCO World Heritage Site, Arizona, United States of America, North America

Historic Hermits Rest, built in 1914, owned by the National Park Service, Grand Canyon, Arizona, United States of America, North America

The back of Historic Hermits Rest, built in 1914, owned by the National Park Service, Grand Canyon, Arizona, United States of America, North America

View of the Grand Canyon east of the historic Watch Tower, managed by the National Park Service, Grand Canyon National Park, UNESCO World Heritage Site, Arizona, United States of America, North America

Panorama view of Tuzigoot Ruins from southeast corner, managed by the National Park Service, Arizona, United States of America, North America

The cattle corral of Lonely Dell Ranch, managed by the National Park Service, at Glen Canyon Recreation Area, Arizona, United States of America, North America

A member of the Scottish Avalanche Information Service demonstrates how to assess avalanche risk on Cairngorm in the Cairngorm National Park in Scotland, United Kingdom, Europe

A view from the Park Service platform where adult brown bear (Ursus arctos) forage for salmon at the Brooks River in Katmai National Park near Bristol Bay, Alaska, USA. Pacific Ocean

A member of the Scottish Avalanche Information Service demonstrates how to use an avalanche probe on Cairngorm in the Cairngorm National Park in Scotland, United Kingdom, Europe

Two curious brown bear cubs (Ursus arctos), inspecting and gnawing on park ranger and service boats at the Brooks River in Katmai National Park near Bristol Bay, Alaska, USA. Pacific Ocean

A member of the Scottish Avalanche Information Service looks at snow crystals to help assess avalanche risk on Cairngorm in the Cairngorm National Park in Scotland, United Kingdom, Europe

Two curious brown bear cubs (Ursus arctos), inspecting and gnawing on park ranger and service boats at the Brooks River in Katmai National Park near Bristol Bay, Alaska, USA. Pacific Ocean

Two curious brown bear cubs (Ursus arctos), inspecting and gnawing on park ranger and service boats at the Brooks River in Katmai National Park near Bristol Bay, Alaska, USA. Pacific Ocean

Two curious brown bear cubs (Ursus arctos), inspecting and gnawing on park ranger and service boats at the Brooks River in Katmai National Park near Bristol Bay, Alaska, USA. Pacific Ocean

Two curious brown bear cubs (Ursus arctos), inspecting and gnawing on park ranger and service boats at the Brooks River in Katmai National Park near Bristol Bay, Alaska, USA. Pacific Ocean

Two curious brown bear cubs (Ursus arctos), inspecting and gnawing on park ranger and service boats at the Brooks River in Katmai National Park near Bristol Bay, Alaska, USA. Pacific Ocean

Saturn, Jupiter and the Milky Way over Balanced Rock in Arches National Park near Moab, Utah.

The Milky Way over Balanced Rock in Arches National Park, Moab, Utah, USA. A small spotlight was used to light paint the rock formation.

Waiter carrying the three most popular beers in Tanzania, Serengeti, Kilimanjaro and Safari, Lobo Wildlife Lodge, Serengeti National Park, Tanzania, Africa

Waiter and waitress carrying the most popular beer brands in Tanzania, Serengeti, Kilimanjaro, Safari and Tusker, Lobo Wildlife Lodge, Serengeti National Park, Tanzania, Africa

Car ferry at the jetty, Kingfisher Bay, UNESCO World Natural Heritage Site, Fraser Island, Great Sandy National Park, Queensland, Australia

The island ferry to Pellworm crossing the icy wadden sea, UNESCO World Heritage Site, Schleswig-Holstein Wadden Sea National Park, North Sea, North Friesland, Schleswig-Holstein, northern Germany, Europe

Cafe terrace at the river bed of the Esen Cay River in a nature reserve, Saklikent, Akdagi Mountains, Fethiye, Mugla Province, Turkey

Edelweisshut on Mt Edelweiss-Spitze, Grossglockner High Alpine Mountain Road, Hohe Tauern National Park, Salzburg, Austria, Europe

Ferry link between districts Niederrathen and Oberrathen on the Elbe river, Climatic Spa Resort Rathen, National Park Saxon Switzerland, Saxony, Germany, Europe

Zwieseler Huette mountain hut on Grosser Arber, 1456m, Bavarian Forest Nature Park, Bavaria, Germany, Europe

Summit cross and Zwieseler Huette mountain hut on Grosser Arber, 1456m, Bavarian Forest Nature Park, Bavaria, Germany, Europe

Signs on the former american penitentiary on Alcatraz, San Francisco, California, USA

Behind Bars: Buildings of the former american penitentiary on Alcatraz, San Francisco, California, USA

US National Park Service sign, Washington, USA, North America

Sign, National Park Service, Hoh Visitor Center, Hoh Rain Forest, Olympic National Park, Washington, USA

Simple hut accommodating the United Jungle Guide Service Book Office, Chitwan National Park, Nepal, Asia

Zwieseler Huette mountain hut on Grosser Arber, 1456m, Bavarian Forest Nature Park, Bavaria, Germany, Europe

A stupa with prayer flags at the Boudha Lodge in Mongla, Khumbu, Sagarmatha National Park, Nepal, Asia

Ferry arriving on the East Frisian North Sea island of Spiekeroog, Lower Saxony, Germany, Europe

Civitella Alfedana, Abruzzi National Park, province of L'Aquila, Apennines, Abruzzo, Italy, Europe

Eisensteiner Huette mountain inn at the Grosser Arber, Bavarian Forest Nature Park, Bavaria, Germany, Europe

Information office of the National Park Service, operators of the National World War II Memorial, WWII Memorial or Second World War Memorial, Washington DC, District of Columbia, United States of America, PublicGround

Eisensteiner Huette mountain inn at the Grosser Arber, Bavarian Forest Nature Park, Bavaria, Germany, Europe

Two climbers dig out their tent after a snowstorm covered them in 14k camp on Mount McKinley, Alaska. Climbers are advised to spare no expense on a expedition-quality tent as it can mean the difference between life and death during a ferocious storm on Denali. Extra poles and repair materials are important in case of damage caused by storms. Plan to take extra pickets, wands or deadmen for tent anchors. Never leave a tent without anchoring it securely. Tents are lost each year due to sudden gusts of wind while the tent was left unattended or drying. Every climbing season High Mountain Rangers of the Denali National Park Service are called to help climbers in need. If possible the patient is brought down to base camp on foot, only in life threatening conditions a helicopter is called to evacuate the patient to a hospital in Anchorage.

High Mountain Rangers Tom Ditola and David Weber are taking a rest on the West Rib on Mount McKinley, Alaska. Mount Hunter in the background. They are above the clouds in blue sky and the sun is shining. Mount McKinley, native name Denali, is the highest mountain peak in North America, with a summit elevation of 20,321 feet (6,194 m) above sea level. At some 18,000 feet (5,500 m), the base-to-peak rise is considered the largest of any mountain situated entirely above sea level. Measured by topographic prominence, it is the third most prominent peak after Mount Everest and Aconcagua. Located in the Alaska Range in the interior of the U.S. state of Alaska, McKinley is the centerpiece of Denali National Park and Preserve. Every climbing season High Mountain Rangers of the Denali National Park Service are called to help climbers in need. If possible the patient is brought down to base camp on foot, only in life threatening conditions a helicopter is called to evacuate the patient to a hospital in Anchorage.

Mountain ranger Brian Scheele on this way to Windy Corner on Mount McKinley, also know as Denali, in Alaska. He is pulling a sled, that together with his heavy backpack is containing all the gear like tents, clothing and food. Every climbing season High Mountain Rangers of the Denali National Park Service are called to help climbers in need. If possible the patient is brought down to Basecamp on foot, only in life threatening conditions a helicopter is called to evacuate the patient to a hospital in Anchorage. Mount McKinley, native name Denali, is the highest mountain peak in North America, with a summit elevation of 20,321 feet (6,194 m) above sea level. At some 18,000 feet (5,500 m), the base-to-peak rise is considered the largest of any mountain situated entirely above sea level. Measured by topographic prominence, it is the third most prominent peak after Mount Everest and Aconcagua. Located in the Alaska Range in the interior of the U.S. state of Alaska, McKinley is the centerpiece of Denali National Park and Preserve.

A mountain ranger is digging out tents after a snowstorm covered them during the night in 14k camp on Mount McKinley, Alaska. Climbers are advised to spare no expense on a expedition-quality tent as it can mean the difference between life and death during a ferocious storm on Denali. Extra poles and repair materials are important in case of damage caused by storms. Plan to take extra pickets, wands or deadmen for tent anchors. Never leave a tent without anchoring it securely. Tents are lost each year due to sudden gusts of wind while the tent was left unattended or drying. Every climbing season High Mountain Rangers of the Denali National Park Service are called to help climbers in need. If possible the patient is brought down to base camp on foot, only in life threatening conditions a helicopter is called to evacuate the patient to a hospital in Anchorage.

Weather station collecting data for the national park and weather service planted on old lava flows in Hawaii Volcanoes National Park

Clouds float above the Painted Hills Unit of John Day Fossil Beds National Monument, Mitchell, Oregon, United States of America

Landscape Of Pine Forests Over Mountains And A Rocky Mountain Range In The Distance, The View Coming Into Jackson Hole, Wyoming, United States Of America

Bronze Statue Depicting People Waiting On A Bread Line During The Great Depression, Franklin Delano Roosevelt Memorial, Washington, District Of Columbia, United States Of America

Martin Luther King Junior Memorial, Located On Four Acres Along Tidal Basin, Dedicated In 2011, 30 Foot Granite Sculpture Called Stone Of Hope By Lei Yixen, Washington Monument In The Background, Washington, District Of Columbia, United States Of America

Grand Teton Range In Autumn, Grand Teton National Park, Wyoming, United States Of America

Statue At Thomas Jefferson Memorial, Washington, District Of Columbia, United States Of America

Martin Luther King Junior Memorial, Located On Four Acres Along Tidal Basin, Dedicated In 2011, 30 Foot Granite Sculpture Called Stone Of Hope By Lei Yixen, Washington, District Of Columbia, United States Of America

Statue At Thomas Jefferson Memorial, Washington, District Of Columbia, United States Of America

Washington Monument, Washington, District Of Columbia, United States Of America

Thomas Jefferson Memorial, Washington, District Of Columbia, United States Of America

Colourful layers of minerals are exposed at John Day Fossil Beds National Monument, Mitchell, Oregon, United States of America

Goat Rock Unit, John Day Fossil Beds National Monument, Dayville, Oregon, United States of America

Sitka National Historical Park Sign At Totem Trail, Sitka, Alaska, United States Of America

Colourful layers of minerals are exposed at John Day Fossil Beds National Monument. No grass grows on the Painted Hills Unit, Mitchell, Oregon, United States of America

Colourful layers of minerals are exposed at John Day Fossil Beds National Monument, Mitchell, Oregon, United States of America

The claystone hills are graceful and colourful at John Day Fossil Beds National Monument, Mitchell, Oregon, United States of America