Topic: Tell me a short, interesting fact about

One fascinating fact about the Roman Empire is that the Romans were among the first to use concrete on a large scale in their construction projects. Their signature concrete, called pozzolana cement, was a mixture of volcanic ash, lime, and water. It's known for its incredible durability, with many Roman structures still standing after nearly 2,000 years, such as the Colosseum, Pantheon, and Aqueducts. This innovative building material laid a foundation for modern concrete technology.