the cathedral plan takes the form of a latin cross, the nave being flanked by slightly lower lateral aisles. it measures in length and across the transversal transept. completed in 1505 by rodrigo de badajoz, the octagonal gothic lantern tower with its three levels of windows rises above the point where the transept crosses the nave. the former apse was later converted into an ambulatory bordered by a series of chapels including the 15th-century st john's chapel (capilla de san juan) and the 16th-century chapel of snows (capilla de las nieves). after the chancel had been demolished in the 20th century, the choir stalls were moved into the body of the church and into christ's chapel.