12. Florence Cathedral, Florence, Italy, Europe
With its 8,300 m2 of the area, it is the twelfth biggest church in the world on our list of biggest churches in the world. Its construction started in 1296 and ended in 1436, so it lasted for 140 years! As we can see the incredible year of beginning, we can claim that this church is the oldest one in our list, but not the oldest one in the world. With its early starting, it is the tenth most ancient one. The world’s largest brick and mortar dome belongs to it.
