In 1419, at the beginning of the Renaissance in ltaly, a clockmaker named Filippo Bruelleschi started work on a very difficult project. He was building the dome of Florence’s main cathedral, the Basilica di Santa Maria del Fiore. At 55 meters (180 feet) above ground, it would be the largest dome built since the Pantheon in Rome was finished 1,500 years before.
After most of the cathedral was built in 1296, many builders tried to complete the dome. But none could do it. No one knew what material to use. Many builders knew how to build concrete domes. However, the dome in Florence needed to be wider than any dome ever built. Also, tall buildings of the time relied on structures that supported the heavy stone from the outside. The cathedral didn't have these structures, so a concrete dome was too heavy. It would easily fall. So, the vathedral's roof was left unfinished for over a hundred years.
Filippo Brunelleschi promised to solve all these problems. He said he would build two domes, an inner dome made of stone, and an outer one made of light bricks. He would use lighter materials as he worked upwards, and would hold it all together with strong rings made of stone, wood, and iron.
Brunelleschi also had to find a way to lift the materials high into the air. What did he do? He invented a new machine to do the job.
Building the dome took 16 years. The crown at the top took another ten. Brunelleschi died a few years later, in 1446. He had done something no one else could. However, he left no pictures of his design. So-even today-experts don't fully understand how this amazing structure was built.