In English we can say we're going to the bank, to Boston, or to Switzerland, but in German there is more than one way to say "to"—and each one of these "to" phrases would use a different German preposition! However, there are some rules and guidelines you can learn for these situations.
Most geographic place names (countries, states, cities, etc.) use nach for "to." Only a few countries that are feminine, masculine or plural (rather than the normal neuter das) use in for "to." Notice the exceptions listed below. For more about countries, see the special Glossary of Nations and Lektion 6.
When going to a location in town, such as to the bakery or a restaurant, the most common prepositions for "to" are in and zu (usually in a compound such as zum or zur).
If you'd like more information about nach vs zu, see How to Say "to" in German. For now, observe the examples in the chart below.