While designs varied greatly during the development and evolution of Gothic cathedral architecture, most came to follow a basic cross-shaped plan as shown to the right.
The main distinguishing feature of a basilica is the rounded apse with a half-dome above the sanctuary, where the altar is located. Many cathedrals in Europe follow this model, but those in England tend to have a square end instead.
The main body of a cathedral is the nave, where the worshippers gather for services. In large cathedrals this is usually bordered by aisles, which as you can see from the cross-section, help to form part of the buttressing of the lofty upper works.
Transepts vary in width and length. Wider transepts may continue the aisles around the corner, while narrower ones may have no aisles.