Dependent drop-down lists in Excel

In a recent entry I talked about how to insert drop-down lists in Excel. Today I would like to show you how to insert dependent drop-down lists. Basically what this means is to have 2 or more drop-down lists with the second one having as content a range that depends on the selection made in the first one. Look at the images below:

There is a drop-down list for a list of countries. Depending on the country chosen, the second drop-down list will display the list of cities from that country.