Sesame Street was first broadcast on November 10, 1969 on the National Educational Television (NET) network which later became the Public Broadcasting System (PBS). This makes sense in that you can still see remnants of the hippie culture that was prevalent in New York City in some of the vintage episodes.
Click for a list and image gallery of Sesame Street Characters
Sesame Street was, and remains, one of the earliest programs with a strong commitment to multiculturalism. The actors (and muppets) cover a wide range of age, ethnicity, color and even physical abilities. The program uses a mixture of puppets, animation and live action to teach young children basic reading and arithmetic, for example, colors, letters, numbers and the days of the week. It also has segments focusing on basic life-skills, such as how to cross the road safely or the importance of basic hygiene.
Controversial issues: the show has never been afraid to skirt the edge of controversial issues in all the languages and countries in which it is produced. An example… when Mr. Hooper died in the early 1980s, the writers decided to portray that in the show instead of simply write him out of the forthcoming scripts. The program actually won an Emmy for the show when Big Bird had to come to terms with the loss of his friend. Another example of multiculturalism and controversy is in the fact that the South African version of the show has an HIV-positive character called Kami. The show produces alternate language versions in Greece, Germany, Netherlands, Poland, and Mexico (called Plaza Sesamo).
Source: the Biography Channel at http://www.thebiographychannel.co.uk/biography_story/857:774/1/Sesame_Street.htm