How was World War 1 and 2 different from previous wars aka colonial conquests?

World War I and II are different from previous wars because of the scale of the war fought. Countries would attack each other's colonies, as well as drawing resources from all over the world. They both included all the European powers, as well as many other European countries, and the United States. Taking over colonies, even those belonging to other countries, would never reach this scale, as those would usually be between 2 or 3 countries. The massive loss of life also sets them other wars: World War II alone cost 15 million soldiers and 60 millions civilians their lives.