These two cities are very famous and tourist destinations there are just simply amazing. One has the famous Sagrada Familia so the other has Duomo Florence. Both of these monuments have a major contribution to increasing the tourism of their cities.
The Sagrada Familia is an unfinished church, which will be finished by the end of 2026 which is exactly 100 years after the death of its designer and famous Catalan architect Antoni Gaudi. Gaudi has many masterpieces in Barcelona such as Casa Batllo, Casa Mila, and the Park Guell. The architect was known for his unique style and design which was inspired by gods and nature.
Sagrada Familia is the most visited place in Barcelona and gets really crowded during the season so always pre-book your Sagrada Familia tickets and avoid late entry or high charge. Because while booking online you can get discounts and combo offers which will be beneficial for you.
And same is the case with Duomo Florence, it is also the most visited place in Florence and is the largest brick ade dome in Europe and one of the largest in the world. You can also climb to the top of the Duomo and have an aerial view of the whole of Florence city. Florence also has the Uffizi Gallery which another very famous attraction of Florence. The Uffizi Gallery has one of the finest artwork present in the world.
These are the most visited places in Florence and it is better to book Duomo Florence tickets in advance to avoid all the rush at the time of entrance, and by booking in advance you might get discounts and combo offers. It's better rather than standing in a long line for a ticket, it gets irritating.