What is your favorite quest room theme?

I really like horror quest room ideas. Recently, I was using https://questfactor.us/ which is a perfect place to have an escape room quest. I liked the Wizarding world and the Mad Scientist escape room theme. It was a nice experience and a wonderful opportunity to have some fun. I am going to have a birthday party in September, so it will be a perfect solution for me. 

Thanks to their service, I really like how they are working, decorations, and overall atmosphere in general. 

I really like horror themes. It's really interesting for me I suppose.