willkommen

German

From Middle High German willekomen, from Old High German willechomen, from Proto-Germanic *wiljakumô. Cognate to Dutch welkom, English welcome, Danish velkommen, and other Germanic forms. Compare also French bienvenu, Italian benvenuto, Spanish bienvenido, possibly Germanic calques.

willkommen

The German word is not used with a following infinitive as in “You are welcome to use my car.” (German: Du kannst gern mein Auto nehmen.).

willkommen

As can be seen from the examples above, willkommen is construed with prepositions of position (not movement) corresponding to the object. Thus, in with countries and cities, an with bodies of water, bei with people, etc., as they are generally used to indicate position.
The preposition zu (“to”) may be used with events and activities: Willkommen zur Weinprobe! (“Welcome to the winetasting!”) However, one may also follow the general rule and use bei, auf, or whatever preposition of position is appropriate.