Text: Brunelleschi's masterpiece, the cathedral's grandiose terra-cotta cupola, with its eight white stone ribs curving to the marble lantern at the top, is the city's symbol, visible not only all over Florence but also from far beyond in the Tuscan hills.
Entailment: There are eight white stone ribs on the cathedral's cupola.
Contradiction: There is no cathedral that can be seen from all over Florence.