Placa Sant Just (St. Justus Square), Barcelona

At the intersection of Hèrcules Street and Dagueria Street in Barcelona lies a square housing one of the city's oldest Christian churches. The 14th-century Basilica of Saint Justus and Pastor overlooking the square stands on the site of a 4th-century Christian basilica, which was the seat of the archbishop until the Barcelona Cathedral was built. The current basilica is dedicated to the boy martyrs Justus and Pastor, who, as recounted by the Roman poet Prudentius, bravely opposed the persecutions of Christians by the Roman Emperor Diocletian. The boys were captured, whipped, and beheaded near the Spanish city of Alcalá de Henares. Some of the relics associated with these saints have been preserved in a chest that is now housed inside the basilica.

Through the glass openings in the floor inside the basilica, you can see the remains of its 4th-century predecessor. The interior of the basilica is full of mysterious surprises, including several images of the damned burning in hell. Only one tower of the two planned was built to give the church its asymmetrical look. You can climb to the top for the awesome views of the Gothic Quarter.

Underneath the square itself, they say, lie the Christian catacombs.

During the Middle Ages, Saint Justus Square was the only place in town where Jews and Christians were permitted to engage in legal trade together. A reminder of that era is the Gothic fountain, the oldest water source in Barcelona, carved of Montjuïc stone in 1367. Back in the day, various commercial transactions and information exchanges took place here. Between its pipes, you can see three human faces carved in stone beneath a relief of Saint Justus flanked by two shields: one royal and one showing a hawk catching a partridge. These are relatively new additions, dating back to the 19th century.