The ivory tower is a way people describe a place where smart people go to think and study. It is like a magical castle in the clouds where only the most intelligent people can go to learn and make discoveries. Often times people compare it to a place where people are cut off from the real world and have no idea of what is happening outside the tower. People who are inside the Ivory tower often are seen as people who don't know anything about the real world because they are too focused on their books and studies. It's sort of like a special club where only the smartest people can join to do their work but can't really connect with the rest of the world.