Florence Duomo - detail of the exteriorTweet
The current façade of the Florentine Cathedral, designed in 1864 in the neo-Gothic style, is made almsot exclusivly of green, white and red marble. It's not difficult to see why it's often criticised for being excessively decorated - but it is consistently decorated in the same design as the Campanile and Bapistry which rank amongst the most important buildings on the Piazza del Duomo.
Most visitors don't stop to look at the façade in any great detail - which is their loss - as there's a lot of detailed carving and sculptures in niches. Even if you don't know who all the saints on the outside are, the decorative aspects are worth spending sometime appreciating.