In many of the “wonders” of our past, information about their meaning and scope has been encoded in the form of astronomical alignments to celestial bodies. Therefore, in many cases, understanding the ideas of the ancient architects turns out to be connected with the study of the relationship of their cultures with the sky. This is the aim of archaeoastronomy, a discipline which is a quite efficacious tool in unraveling the original projects of many monuments. This issue is briefly discussed here by means of three examples taken from three completely different cultures and historical periods: the so-called “air shafts” of the Great Pyramid, the urban layout of the capital of the Incas, and the design of the Pantheon.

Peru and France are to conclude an agreement to provide Peru with an astronomical observatory equipped with a 60-cm diameter telescope. The principal aims of this project are to establish and develop research and teaching in astronomy. Since 2004, a team of researchers from Paris Observatory has been working with the University of Cusco (UNSAAC) on the educational, technical and financial aspects of implementing this venture. During an international astronomy conference in Cusco in July 2009, the foundation stone of the future Peruvian Observatory was laid at the top of Pachatusan Mountain. UNSAAC, represented by its Rector, together with the town of Oropesa and the Cusco regional authority, undertook to make the sum of 300,000€ available to the project. An agreement between Paris Observatory and UNSAAC now enables Peruvian students to study astronomy through online teaching.