We're from the Netherlands and we choose Harlem because of the name. We have basic knowledge about the history between America and the Netherlands, but during this tour we definitely got our lessons learned about our history in NYC.
Our tour guide was Katherine, with a K. It was quite hot during our tour, but she made sure we were able to sit down during the walk if needed. Our group was not the only group having the tour that day, but what I noticed was that Katherine was the only tourguide with a tablet with her. She used the tablet to let us hear music which had hidden meanings to it in connection to slavery and gospel. Very unique! Besides the explanation of gospel she let us hear the beginnings of the music type, which was truly amazing.
She also explained some architecture with relations to African Americans.
I don't want to give to much away, because you have to experience the tour yourselves. But in my opinion: you can't leave America without this tour done by Katherine!
In the end we attended a church service. Our entire group almost filled up the room, but the regular church visitors didn't mind at all and one person even helped me find the song in the little book they gave us to sing along. Our group also gave us a hand fan because of the heat, which was very kind and we used that fan afterwards too.
In short, if you do this tour ask for Katherine! She gives you the full experience with some street art, architecture, history and music of which you never knew the hidden meaning behind it. It's definitely worth it.