1. Cattedrale di Santa Maria del Fiore
What is it: An absolute must-see in Florence (and to be honest, you can't miss it). The Cathedral of Saint Mary of the Flower (or the Duomo, as it's better known) is the centre point of the city's heart.
Why go: The Duomo was built in the 15th century and was the largest church in the world at the time (now it's the third biggest in Europe, which is still pretty big). If you can face the 463 steps, it's well worth the climb to the top of the dome, as this is the highest point in Florence. Trust us, that view over the city's cascading buildings and terracotta rooftops is worth it.