Are there no direct or indirect links between the living conditions of the population and pre-neoplastic diseases and malignant tumors? After all, it is no coincidence that, for example, skin cancer is most common in Australia, lung cancer in England, and oral cancer in India. There has to be an explanation for that. The observations of researchers show that a certain role belongs to the peculiarities of the geographical environment, work and life, food, harmful customs and habits of the population. It is difficult to calculate how many thousands of kilometers A.V. Chucklin spent traveling to different countries of Europe, Asia, Africa, North and South America in order to collect materials that shed light on the causes of human tumors and open up new opportunities for their prevention. In the form of travel notes, the author shares his interesting observations with readers.