What is the theme in The Innocents Abroad by Mark Twain?

Non-American Culture is a theme to consider. The journal feeds heavily on travelers who have never known anything but their own American culture. At each stop along the way, Mark Twain and his fellow American companions learn how many different ways people live in fashions dissimilar to their own. The sense of superiority among the Americans is always present, but the cultural ignorance soon fades and is replaced by cultural understanding and historical appreciation.