Dating from 1370, the Spalentor is a fortified gate marking the end of the old town. The town gate, once part of the old town walls, has stood alone since their destruction in 1866. Look to the left of the gate to find an early 19th-century letterbox with the emblem of the Basel pigeon. The adjacent Peterskirche (St. Peter's Church) was rebuilt in the 15th century, but the vaulting in the choir is from an earlier 14th-century building. There are frescoes in the Eberler chapel and the nave. Adjacent is the university, with a botanical garden that was founded in the 16th century, one of the oldest in the world.