The distinctive characteristic of Gothic cathedrals of the Iberian Peninsula is their spatial complexity, with many areas of different shapes leading from each other. They are comparatively wide, and often have very tall arcades surmounted by low clerestories, giving a similar spacious appearance to the 'Hallenkirche of Germany, as at the Church of the Batalha Monastery in Portugal. Many of the cathedrals are completely surrounded by chapels. Like English cathedrals, each is often stylistically diverse. This expresses itself both in the addition of chapels and in the application of decorative details drawn from different sources. Among the influences on both decoration and form are Islamic architecture and, towards the end of the period, Renaissance details combined with the Gothic in a distinctive manner. The West front, as at Leon Cathedral, typically resembles a French west front, but wider in proportion to height and often with greater diversity of detail and a combination of intricate ornament with broad plain surfaces. At Burgos Cathedral there are spires of German style. The roofline often has pierced parapets with comparatively few pinnacles. There are often towers and domes of a great variety of shapes and structural invention rising above the roof.

What is the distinctive design element of Gothic cathedrals of the Iberian Peninsula?