Friday, June 7th at 10.30am, Joaquim Alves Gaspar will deliver a talk at the Faculty of Sciences, University of Lisbon, room 8.2.14. All welcome. Brief summary We know from Antiquity that the Earth is round. Not only did the Greeks produced solid arguments that the surface of our planet was curved but also, they estimated its circumference with a remarkable accuracy. The shape and size of the Earth was not, however, a relevant practical subject for the Europeans during the Mi