A global project in collaboration with: La Main à La Pâte; Bibliotheca Alexandria; Universidad de Buenos Aires; Universidade Federal de Itajubá; Astrofanaticos (Colombia); Space Adhyaan(India); Parque Cielos del Sur (Argentina) Students from all continents cooperate and collaborate to reproduce one of the science's 10 most beautiful experiments of all time: Eratosthenes' measurement of the Earth's circumference.