Although his modifications scandalized some of his contemporaries, such changes are in no way foreign to Gothic architecture. Medieval cathedrals were often constructed and reconstructed over many generations, their architectural fabric changing bit by bit at the hands of builders with evolving standards of architectural beauty. A case in point is Chartres Cathedral, about 90 kilometres southwest of Paris. Its west façade was originally dominated by nearly symmetrical towers built in the 12th century. When the north spire was destroyed by lightning in 1506, it was rebuilt taller and in a more elaborate style. This striking asymmetry makes the cathedral a moving document in