But more importantly, in these 20 years, he has a unique academic path and rich experience of overseas investigation. "I have been to more than 40 countries, and the key is to go to developing countries," said Wen Tiejun in a low voice with a slight Beijing accent, "I am one of the first people in China to investigate large slums in developing countries, so in recent years I have repeatedly called for discussions at the policy level: all developing countries with a population of more than 100 million have failed urbanization and have created large slums. Slums are the root cause of social unrest, the place where prostitution, gambling and drugs are rampant, the place controlled by the mafia, and the place where regular police and regular rule of law societies cannot be established. Therefore, China must be vigilant, we can not follow other developing countries to accelerate the process of urbanization through large slums."