Need suggestions about Dortmund

Recently my friend came back from Dortmund. This name is new to me. She told me Dortmund is a City in Germany. She has a great experience with this city. After hearing about her travel story I am keen to visit this spot. But I am busy these days so I decided to go to Dortmund next year. Do you have any best memories with Dortmund?

Excited about the bus tours to chicago.

I feel bad to say that I have no idea about this city. The name of this city is new to me. I have never visited in my life. If you want to receive any information you must share it with me. Then I must go there. Anyway, If you go to take this city tour must share it with me.

Sure, I will share about this spot here. But I have no plan yet to go there. Anyhow, I enjoyed the New York tour and I had a great experience with this city. So I want to know your experience with this destination. So if you visited this spot then Share here your favorite place that you explored there and Cannot forget this experience in a lifetime. Waiting for your reply...