Kattigara is a place that existed a long time ago, which we now call Vietnam. It was a place where people lived and traded with other parts of the world, including the Romans and the Greeks, who lived very far away. People traveled from all over to trade and do business in Kattigara. It was a very important and bustling place, kind of like a big marketplace. Today, Kattigara is still an important place but it's now called Vietnam and has changed a lot over time.