In comparison to others, the Vikings were quite advanced in some areas. Their shipbuilding and combat abilities were unrivaled. They did, however, need to plunder and conquer to keep up with their rising numbers. Their ships and swords were quite detailed, runes were engraved into their weapons, and creatures were carved into their ships. The Vikings discovered how to construct structures out of two types of wood: birch and coniferous trees. To adapt to the material they chose, they created two separate construction styles.