3.1 million visitors Red Light Strip
In 2017, about 3,100,000 people walked along Red Light Strip (Oudezijds Achterburgwal), according to the number of unique WiFi signals in the area. Mobile phones that occured several times during the day were excluded from the result, assuming these were locals who live or work in the area.
The most busiest day of the year was 9 September, with a total of 14.657 visitors. Second and third place are for 11 November and 29 April. There is no obvious reason why these days are in the top 3. Red Light District is often referred to as being too crowded. Compare this: on a regular Saturday, shopping street Kalverstraat attracts 40.000 people.