From the National Geographic book Journeys of a Lifetime

The Wind River Mountains, Wyoming

The mountains climb over 13,00 feet (4,000 meters) into the skies southwest of Dubois in Wyoming. Native American tribes hunted here, and their rock drawings and paintings are visible from the trails. In late September, moose chase each other through snow willows, and the hillsides are ablaze with orange and yellow cottonwood. There are more than 155 miles (249 kilometers) of trails.

The Milford Track, New Zealand

Described by hiking aficionados as the finest walk in the world, the track—from Glade Wharf on the northern shores of Lake Te Anau to Sandfly Point near Milford Sound on the west coast of the South Island—takes four days. The track starts by meandering through the beech-tree forests of the Clinton Valley, climbs to the Mackinnon Pass through subalpine tussock and alpine herbs, and then descends into the more diverse forest of the Arthur Valley with its ferns, mosses, and lichens. ,

Concordia Trek, Pakistan

Situated on the border of Pakistan and China, Concordia is a remote and isolated place. Huge glaciers spilling from the mountains of K2, Broad Peak, and Gasherbrum meet here and melt to form tributaries of the Indus River. It is a 14-day trek from Askole to K2 base camp. At the end of the trip, refresh your tired body in the hot springs in the Braldu Gorge near Askole.

The Pindos Traverse, Greece

The mountains of the Pindos stretch 180 miles (290 kilometers) from the Gulf of Corinth to the border of Albania. The highest of these mountains are over 6,500 feet (2,000 meters), and even on the sunniest days the air is cool. In springtime the wildflowers are among the loveliest and rarest in Europe.

Haute Route, Corsica, France

This 124-mile (200-kilometer) trail crosses the spine of mountains that run the length of the island, from Conca in the southeast to Calenzana in the northwest. The walk will take you through high mountains and pine forests frequently punctuated by clear streams and pools. There is the occasional snowfield to cross early in the summer.

Haute Route, France/Switzerland

The Haute Route, from Chamonix in France to Zermatt in Switzerland, is a demanding two-week trek through some of Europe’s highest peaks, linking Mont Blanc with the Matterhorn. The paths are not heavily used, and there is a superb variety of Alpine flowers. Wildlife includes ibex and chamois as well as the marmot with its shrill alarm call.

Pyrenean Haute Route, France/Andorra/Spain

For the purist, the Pyrenean Haute Route starts on the shores of the Mediterranean and finishes 44 days later on the shores of the Atlantic Ocean. However, most people tend to walk the middle section, taking about 24 days from Lescun in France to El Serrat in Andorra. Many of the mountains in the Pyrenees are over 9,800 feet (3,000 meters), and the Haute Route often crosses the tops of them.

The Southern Upland Way, Scotland

Scotland’s longest trek stretches 211 miles (340 kilometers) west to east from the old fishing village of Portpatrick to the dramatic North Sea cliffs of Cockburnspath. The trail is varied, sometimes plunging deep into dense fir forest, at other times crossing high moorland.

The Pennine Way, England/Scotland

The Pennines, a range of high moorland hills, form the backbone of England. The Pennine Way is a long-distance footpath running the length of these hills from Edale in Derbyshire to Kirk Yetholm in Scotland, 250 miles (402 kilometers) to the north.