Hamburg Town Hall

This photo is an experiment. I took the photo around 2 pm, i.e. in the middle of the day. The square in front of the town hall was full of people. Tourists, employees of the various businesses that have their offices in the city center, people who went shopping and so on. How do you get a picture with no people (except me looking at the building)?
I took every 30 seconds a new picture, 20 pictures altogether. At home I stacked the pictures as different layers. I only needed three layers with the people at different positions. Using masks I blended the pictures in such a way that the empty spots remained in the final picture.
What do you think?