I WONDER - Why Did The Celts Have Burial Mounds?

The transcript describes ancient burial practices where bodies were placed in stone chambers and covered with earth. Items the deceased liked, along with supplies for a party, were buried with them. The Kelts believed that upon reaching the afterlife, they would need to host a party, so they were buried with wines and foods. A good leader was expected to be generous, thus buried with many items for the feast.

How did the Kelt view the afterlife in relation to celebrations?

What was expected of a good leader in terms of burial practices?