Apart from the new tolerance for behaviour that was technically still illegal, and viewed by a large part of society as immoral, there were other developments in Berlin culture that shocked many visitors to the city. Thrill-seekers came to the city in search of adventure, and booksellers sold many editions of guide books to Berlin's erotic night entertainment venues. There were an estimated 500 such establishments, that included a large number of homosexual venues for men and for women; sometimes transvestites of one or both genders were admitted, otherwise there were at least 5 known establishments that were exclusively for a transvestite clientele. There were also several nudist venues. Berlin also had a museum of sexuality during the Weimar period, at Dr. Magnus Hirschfeld's Institute of Sexology. These were nearly all closed when the Nazi regime became a dictatorship in 1933.