What are the motifs in The Innocents Abroad by Mark Twain?

One recurring idea that seems to bore Mark Twain to the point of bitterness is the practice of foreign lands to profit off of their own histories. At every stop along the excursion, old buildings and historical landmarks demand compensation before anyone can appreciate them. Twain does enjoy the history of the lands, but his sarcasm and sometimes bitterness indicates that he does not like these histories shoved down his throat. Even though Twain is a good sport about describing the details of each land, the descriptions sometimes feel forced. It is his distaste for taking something that a person should be able to freely stare and wonder at and charging a fee for it.