On the 4th day the participants of the EAAE-IAU Course set on to CosmoCaixa by bus.
At CosmoCaixa the participant were received by Alejandro Fernández, the Director of the institution, who presented the institution through a general lecture called "CosmoCaixa. Ten years of disclosure of science", followed by a guided tour around the perimeter.
Josée Sert and Cristina Palici presented a General Working Group about the "International Year of Astronomy 2009: Results and perspectives".
In the afternoon Veselka Redeva, Alexandre Costa and Alan Pickwick made a presentation about nighttime observations, concerning observation activities with the Moon and Deep Space objects, as well as explanations about telescope functioning.
After a free visit to the Science Museum and a Planetarium Session, the group then followed to the Center of Madrid for a free tour.