Why did Vikings leave their homeland to explore other areas?

The Vikings traveled thousands of miles across the sea from their homeland of Scandinavia where they were farmers, fishermen, seafarers and traders. Denmark had a lot of sandy soil. Some historians believe the Vikings left their homes because of over crowding. There was not enough good land for everyone to share.

The main reason is due to over population and not having enough room at their homeland, but thats not the only reason.