The cathedral interior is to a basilica pattern; it's vast and at first feels dark and empty. Give your eyes time to adjust, and admire the stain glass windows, funeral monument of Bishop d'Orso, and altar of St Zanobius. Below is the Crypt (M-Sa 10:00-17:00) with remains of the preceding cathedral of Santa Reparata, and the tomb of Brunelleschi. Giotto is believed to lie here somewhere, but his tomb has yet to be identified. Above is the soaring cupola or Dome. The cathedral itself is free, but you need a pre-booked ticket and time slot to climb the 464 steps up to the Dome (entrance north side of the church). Slots are available M-F 08:30-19:00, Sa 08:30-17:00 and Su 13:00-16:00.