Why do people leave home to travel according to the passage?

People enjoy taking trips, but what are the reasons they leave home? (17[D]) One reason is for education. People travel because they want to broaden their horizons to learn about other people and other places. They are curious about other cultures. When people are tourists, they get a quick look at different ways of living. Even a short look at another kind of lifestyle is an important lesson.
     (20[B]) On a trip, a person can learn directly — by visiting museums and historic spots. (18[C]) What does a tourist learn who sees the art museums, visits the historical palaces and other scenic spots in Paris, and shops along the River Seine? He gets a vivid picture — a real-life one — of the French people. He learns about their attitudes, how they feel about business, beauty, and history.
     What about the tourist who goes to Hong Kong? Does he get the same information that he could get from a book? He might read that Hong Kong is crowded, that there is less than 200 square meters of space for each person, but seeing and feeling the lack of space will impress him much more. He might read that there are nearly 200 vehicles for every kilometer of roadway, but the sight of so many vehicles parked along the roadside will be a much more vivid lesson. (19[A]) The tourist to Hong Kong will never forget the contrasts — the straight vertical lines of the tall modern buildings and the moving lines of boats that the people live in.