It's almost impossible to imagine life without the comfort of our beds, the convenience of 24-hour superstores and the thrill of a luxury vacation, but there are some communities that know a very different way of life. From the Tuareg, who spend their lives roaming the Sahara Desert, to the Nenets, who migrate 800 miles (1,287km) every single year, these are the world's last surviving, and most fascinating, nomadic tribes.