The ancients nomadized with their flocks and herds for the sakeof finding pasture and hunting grounds. Wittingly or not， they spreadthe seeds of primitive civilization all over the world. However， thisprocess seemed endless in the age of small-scale production， whenpeople were completely isolated from each other， though the crowingof their birds and barking of their dogs were within earshot. Someof them remained in their native land for their whole life; othersdevoted their whole life to exploiting new frontiers. The socializedlarge-scale production has given a great impetus to human flows. Theglobalization of the economy has expanded human activities to everycorner of the world.
Nowadays， human beings crisscross this blue planet， reaching farbeyond the boundaries of their ancestors. They have greatly expandedtheir sphere of activities， particularly due to the advent of moderntransportation tools. Xun Zi （Hsun Tzu）， a great Chinese philosopherof two thousand years ago， said： “Horse riders， though not fleetfooted，can travel thousand miles; Boat sailors， though not goodswimmers， can get over turbulent rivers.”
We should now add “Aircraftflyers， though not winged， can travel through the sky.” Aircraft makesit possible for travelers to reach the other side of the planet withina single day. The advancement of transportation means has greatlyincreased the traveling ability of mankind.
Traveling facilities have greatly promoted exchanges as well as collisions among different cultures and social systems. People around theworld learn from each other， condone each other， and intermingle witheach other. Thus， they have moved forward and diversified the cultureof mankind. They have rendered our planet into a more colorful andwonderful place. Human beings of modern day have gradually graspedthe concept of “citizens of the global village” while they strive for existenceand development.
As Confucius is quoted in the Analects of Confucius， “Within the fourseas all men are brothers.” This simple and plain ideal of the ancient timehas been accepted by more. According to DNA sequences and structures，scientists infer that mankind may probably evolved from the sameancestor， that is， “Lucy”， who lived 3，200 thousand years ago in the EastAfrican Great Rift Valley. Her descendants probably left Africa about 6thousand years ago and spread to the rest of the world and then evolvedinto races of different colors with different languages. This archeologicalfinding has provided genetic basis for the idea of “Within the four seas allmen are brothers. For more than one hundred years before the turn of the last century，China was self-isolated and cut off from the outside world. But its gatewaywas forced open by imperialist powers with modern guns and cannons.
After the new China was founded in 1949， some foreign powers imposeda blockade and embargo against the new nation. It was not until the endof 1970s that China opened its door and ushered in a new era of opendoorreforms. A large number of Chinese have visited foreign countriesand numerous foreigners have come to China. This inflow and outflow oftourists have added splendid colors to a world culture.