The transept and the apse were built atop the Romanesque crypt, making them a little higher than the nave; they are reached by a short stairway, giving the impression that the choir and apse are the stage of a theater. The crossing of the transept and the choir is topped by the central cupola or dome, which is supported by four gigantic pillars, each wrapped in eight columns, which reach up to support the vaults under the cupola. The cupola itself rests upon four squinches, a base made of rounded arches, which make the connection between the Gothic and Romanesque elements. The columns are lavishly decorated with sculpted foliage.