A heiau is a special kind of Hawaiian temple that was built a long, long time ago by the Native Hawaiians. It was a place where people could go to worship their gods and goddesses, or to ask for their help with important things like growing crops or winning battles.
The heiau was built with big rocks called stones, which were carefully placed on top of each other to make walls or platforms. These stones were so heavy that it took many people working together to move them!
There were different kinds of heiau for different purposes. Some were used for making offerings to the gods, while others were used for special ceremonies or rituals.
Today, many of these heiau are still standing in Hawaii, and people go to visit them to learn about the history and culture of the Native Hawaiians. They are very important to the people of Hawaii, and are a reminder of their spiritual and cultural heritage.