To start their epic journey they travel high into the Andes where they must become chagras - the weathered, hard-as-nails cowboys of Ecuador. They do battle with the local, deadly fighting bulls, many of which end up in bullrings across South America.

Continuing their epic journey they travel to the Siberian arctic to become Evenki reindeer herders, a people who have survived in one of the most hostile locations for thousands of years. This is about learning to deal with extreme cold without home comforts.

The adventurers head into the jungle of Mexico's Yucatan peninsula and become cave-divers in a vast network of largely uncharted, pitch-black, underwater tunnels.

The adventurers join boys of the Jaminawa tribe in the Brazilian Amazon and endure six days of a jungle initiation to become men. To succeed they must follow the rules of Jaminawa shaman Carlito, who has taught generations of boys the secrets of the jungle the hard way.

After two months on the road, they have arrived in blistering heat of the Namibian bush for their fifth challenge - to join the Ju-Wasi tribe of San Bushmen on a traditional hunt in an extremely inhospitable environment.

After the pain of the Amazonian jungle and the arid heat of the Namibian bush, they have come to paradise - the Bahamas. Unfortunately for them their challenge lies underwater, in the shape of sharks.

The lads' penultimate challenge is going to be one of the most deadly, as they have come to Bangladesh to learn to catch venomous snakes. Master snake king Shoporaj Dholu has just six days to train them up and keep them alive.

They have reached Japan for the last of their challenges. They have just six days to become Buddhist Yamabushi monks and take part in one of the toughest pilgrimages on the planet to the summit of a sacred mountain, under the watchful eye of Miyagi-San, their Master.