Mound builders were people who lived long, long ago - even before your great-great-great-great-great grandparents were born. These people lived in North America and they built big, big mounds of earth.
Now, these mounds were not just any ordinary piles of dirt! They were made by the mound builders as a way to honor their ancestors and religious leaders, who they believed had special powers. They also used mounds as platforms for buildings or as burial sites, which means they put people who had passed away inside the mounds.
These mounds were sometimes as tall as three or four houses stacked on top of each other! They were built over many years, using baskets, shovels, and whatever tools the mound builders had available.
The mound builders built different shapes of mounds. One shape was a circle, and another was a long and narrow shape like a snake. Another shape was a pyramid, which means it had four sides that went up and covered with dirt. They were very creative!
Today, we can visit many of these mounds in North America, like the Monks Mound in Illinois, which is one of the biggest mounds ever built! The mound builders were amazing people who left behind a lot of history and interesting stories for us to learn and admire.