RailEurope Rail Passes are generally the best option for exploring multiple countries in Europe, or even for doing lots of traveling within a single country.

There are several types of passes available, one for just about every situation. The Global Pass can be used for as many as 18 countries for a varying number of days.

Be sure to look at the pass saver if you are traveling with one or more companions. And if you are under 26 there are some youth pass options.

Senior passes offer savings for those over 60 years of age

Multi-country passes are available for traveling among three, four, or five bordering countries.

One Country passes are also available for almost every country in Europe. There are more countries added each year.

For those of you who want to take a train to a city or town and then have the flexibility to drive around the countryside, you may want to consider the Rail and Drive pass.

Point to point tickets are available if you just want to travel from one point to another. As an example you could fly into Paris, take a train to Nice or Milan, for instance, and fly home from there. Or You fly into Rome and buy a round trip ticket to Florence and fly home from Rome. There are so many options!

A few things to consider: When traveling with a pass, you will need to pay for seat reservations on the premier trains such as Euro Star and the TGV. When traveling on a overnight train, the charges are based on the type of accommodation you prefer.

Frommers has a great guide to the merits and pitfalls of buying your tickets in Europe or before you go abroad.