The only country Denmark has a land border with is Germany to the south.
Germany is the only country to border Denmark.
Germany has a land border with Denmark.
Germany!
Germany
Gemany
Germany is the only country to have a land border with Denmark.
Denmark is located on the northern border of Germany.
Germany
Denmark
The Aland Islands are part of Finland, which is telephone country code +358.
Germany is the only country that shares a land border with Denmark. Considering you've tagged Germany in the question, I get a feeling you already knew...