Perhaps travel cannot prevent bigotry, but by demonstrating that all peoples cry, laugh, eat, worry, and die, it can introduce the idea that if we try and understand each other, we may even become friends.
Courage is the most important of all the virtues, because without courage you can't practice any other virtue consistently. You can practice any virtue erratically, but nothing consistently without courage.
I am sure it is one's duty as a teacher to try to show boys that no opinions, no tastes, no emotions are worth much unless they are one's own. I suffered acutely as a boy from the lack of being shown this.
Let the new faces play what tricks they will
In the old rooms; night can outbalance day,
Our shadows rove the garden gravel still,
The living seem more shadowy than they.