Red Light District
You must visit this neighborhood if you visit Amsterdam. The area with the girls are narrow streets with some red lights on the doors, that are like cabins. WHen I went (last Christmas), they were cheeky, so I recommend that you have your bags and wallets safe to not be robbed. Some girls were very young but there were older ones and obese ones. Incredible. I recommend to visit the sex shop and the erotic museum where you can find interesting objects at a good price. It´s totally normal to pass by and look. The store of the preservatives (I don´t remember the name, it is very interesting, now I will put up photos.