The area code (phone code) 0228 is assigned to 3 locations in Germany. Mainly you reach landlines in Bonn (Nordrhein-Westfalen).
Note for calls from abroad: In addition to the German country code (+49 or 0049) you can omit the foregoing zero of the dialling code for Bonn. So you can dial +49228... and add the number of the phone line you want to reach.
"Which" is spelled with "wh", not like I see it now in the question:Wich place is a "must see" for a tourist in Bonn?