Old Romanesque church from the 12th century that in 2015 became an astronomical center. The only Meridian Line that can be visited in Spain that works through the different light inputs, indicating the solar noon and the months of the year. The Estelarium, with a recreation of the constellations visible on the sky of Becerril de Campos, through the vault with a reproduction of the firmament. A Foucault Pendulum installed in the apse of Saint Peter, showing the movement of the earth’s rotation. Declining sundials that tell the solar time during the day. Several Pinholes, including one Austral, through which the Sun enters and is projected on the Meridian Line marking the exact noon throughout the year. At 12:00 noon, it is observed how sunlight flows through the Becerril meridian, which crosses the Castilian region of Tierra de Campos.