Template:IsIn

Syntax:

This is an empty template creating the breadcrumbs-trail-navigaton.

This is how it works:
 * In the article of Europe you set  isin: Earth , because Europe is a continent on earth.
 * In the article Germany you set  isin: Europe , because Germany is a country in Europe.
 * In the article of Bayern you set  isin: Germany  because Bayern is a state in Germany.
 * In the article of Munich you can now set  isin: Bayern , which means that Munich is a city in the state of Bayern.

On top of the Munich article you now can find the following navigation:

Earth > Europe > Germany > Bayern > Munich

That's it!

Note: the Template:Infobox German Location automatically adds this template and fills in the appropriate federal state (“Bundesland”) (as well as it categorises the article) according to the parameter “state” if it is given. Similar thing does the Template:Infobox Country.

Logical classification
At the moment, the navigation is build as followed. It would be nice if all article navigations look uniform:

Earth > Continent > Region of the world > Country/Nation > State within the country > City

Sometimes it's unclear which country belongs to which region of the world. For this, check the continent articles of Europe, Asia, Africa and Americas. Here the countries are spread over the different regions of the world as defined by the UN.

If you have no idea to which state a city is belonging, check the city article on wikipedia, it often tells you in which state the city is located. Often the state articles for many countries still don't exist. Don't hesitate to be the first to create a state article ;)

If you have better ideas to classify the navigation, you're welcome to discuss about it here. Also this is the best place for your questions.