Nothing gets vacationers in Europe moving like the continent's extensive rail system.
It's possible to wake up in one country, get on a morning train and pass through two or three other countries by lunchtime. The first of these rail deals is for the college-aged crowd, while the second is for everyone. Few tourist groups use the rails as frequently as the summer backpacking crowd. In their late teens and early twenties, they're curious about these countries they've heard their teachers drone on about in classes for years. They are on tight budgets, and know the rails are the smartest and cheapest way to see the Old World.