BOLBEWONERS' - Dutch for: 'Earth inhabitants' or 'Globe trotters' - is the title of a reading book on spherical geometry, designed in dialog with pupils of grades 4 and 5 (primary school). Four children - Willemien, Kikkie, Noor and Frank - are characters in the story. They build a cottage and a mysterious professor X enables it to fly. Taking off, the straight horizon becomes a curved line! This one and a lot of other problems, conflicts and solutions appear during the world trip. For example, how to understand the earth is both spherical and flat at the same time? A sensational result was pupils identified with the characters of the story. Points of discussion in the story were continued anew by the pupils in school. Internet setted in as a helpdesk: pupils in the classroom could communicate with all BOOK CHARACTERS - acted by some mathematics teachers (internet site Pupils of different schools in the world (Amsterdam, Carribean) asked questions - often too difficult for their teachers. The internet site provided them also with the equipment to take satellite pictures from their own and other person's position to investigate the earth from different viewpoints. Moreover the site contained animations to gain a deeper insight into geometrical concepts incorporated in the book and to have children experiment, like driving a dinkey toy on a globe.