Museo del Foro de Caesaraugusta

This museum is located in the Plaza de la Catedral de la Seo, across the square from the Basilica del Pilar, so it's hard to miss. This museum is part of the Roman route that runs through Zaragoza, together with the Public Baths Museum, the River Port Museum, and the Theatre Museum. Admission is €2.50, but you can buy a joint ticket for the four museums for €7 (€5 if you are students). You're allowed to take pictures inside, though not using flash. The museum has three floors, although the ground floor has nothing but the reception. Upstairs, you can see the remains of the ancient Roman forum and the market.