Tribal beauty: Photographer gives snapshot of vanishing way of life

(CNN) -- As teenagers, the women of the Ethiopian Mursi tribe pierce their lower lips and put a clay plate in it. They are one of the last tribes in the world who still practice this tradition and the new generation, influenced by the outside world, might decide to abandon it.

That's why British photographer Jimmy Nelson decided to travel the world for three years, visiting 35 tribes in all five continents, to document their lives and customs before they disappear.

British photographer Jimmy Nelson spent three years traveling to remote areas of the world to document the lives of indigenous people. He visited 35 different tribes, nine of them in Africa, like the pictured Karo tribe in Ethiopia. The Banna people (also known as Bana) in Ethiopia are approximately 45,000 in number. They are famed for their "bull jumping" ceremony, where the men earn the right to marry by making four runs over the backs of cows.

The Dassanech in Ethiopia, pictured, will allow anyone to be one of them, as long as they agree to be circumcised, Nelson explains.

An estimated 200,000 tribal people live in the Omo Valley in Ethiopia. The Karo are small in number with around 3,000 living on the Omo River's eastern banks. Before a ceremony, they paint their bodies and faces with white chalk.

Nelson says he had to gain the trust of the tribes before they would let him take their portraits. "You make one contact and before you know it, somebody else is there. And at the end of the day the whole village is in," Nelson says.

Nelson visited the African tribes during five trips to the continent. He says that the Kenyan Samburu are more traditional than the Maasai and more independent and egalitarian.

Nelson grew up in various African countries until the age of seven. But he says his childhood isn't there anymore. "Africa is evolving the quickest in my opinion. It has lost the majority of its ethnicity and authenticity," he says.

From a very early age, the Maasai boys learn the responsibilities of being a man and a warrior. The Maasai live in Kenya and Tanzania.

Nelson says the most challenging part of his African journey was approaching the Ethiopian tribes, like the Mursi, pictured. He says they were very protective of their territory, and he was often greeted by men carrying Kalashnikov rifles.

One thing that stood out to Nelson when meeting the different African tribes was their awareness of their appearances, including the "beautiful" Himba.

The British photographer visited one of the last great warrior cultures -- the Maasai (pictured). The Maasai are one of Africa's best-known tribes.

Nelson said the most pleasant trip was visiting the Namibian Himba. "The aesthetic of their body, of their dress, of their dance and of their movement I find extraordinary and very few of us will ever look as beautiful as them," he says.

The 45-year-old photographer says his book is just the beginning of a larger project. He wants his photographs and stories to inspire discussion. "In my eyes the tribespeople are emotionally and socially very rich but materially very poor, and we're the opposite," he says. "How aware of how special they are is debatable, hence why I want to start this discussion. Before they pass away."