When God was creating the world some years ago, he did not omit to draw borders, and rivers, and mountains, as many as seemed good to Him. Today, people around the earth tend to see these elements in two contradictory ways : either as unsurmountable obstacles, or as natural riches. Flavie and Samuel are from this second group, and the journey they have decided to undertake together must be seen as an opportunity to promote and enhance human nature. They are the scouts who do not only shed light on the world but who, by their confrontation to the world, enlighten us and give us material to write books, to compose songs, and to think properly. They are the means to reach a better end and to make steady progress. They are our family, our friends, our heroes. They are the railway adventurers.