A few days ago in Saint Augustine, Florida, we went and saw a castle called Castillo de San Marcos. It was built in 1695 to protect St. Augustine which is actually the oldest city in the United States. It is a castle that has four corners and a courtyard in the middle. The four corners are filled with earth so they can support the weight of the cannons on top. The fort had a shot furnace. It’s like an oven that heats up cannon balls until they turn red. Then they shoot them at ships to burn them up.
The castle was made of coquina stone. Coquina stone is made of tiny sea shells smushed together.