Sesame Street: How to get to ... 40 years

Sesame Street in 1969: Big Bird, Mr Snuffleupagus and Barkley the Dog Photograph: c.Henson/Everett/Rex Features

1969: Cookie Monster Photograph: c.Everett Collection/Rex Features

1969: Public TV series Sesame Street featuring Big Bird Photograph: Bill Pierce/Time & Life Pictures/Getty Images

1989: The Sesame Street gang celebrate their 20th anniversary Photograph: c.Everett Collection/Rex Features

1999: A 33-cent US stamp, honouring 'Sesame Street', featuring Big Bird Photograph: US Postal Service/AP

2002: Joe Lamond, president and CEO of NAMM-International Music Products Association, testifies with Elmo, the Muppet character from television's Sesame Street, before Congress Photograph: Scott J Ferrell/Congressional Quarterly/Getty Images

2002: The first HIV-positive Muppets character joined the existing cast of the 'Takalani Sesame', shown in South Africa Photograph: Reuters

2004: Zuzu, Kami and Zikwe from Takalani Sesame the South African adaptation of Sesame Street with Desmond Tutu and Oprah Winfrey Photograph: Kevin Mazur/WireImage/Getty Images

2005: Sesame Street character Cookie Monster shows a basket of fruit in the 'Happy Healthy Monsters' series Photograph: Richard Termine/AP

2006: Laura Bush meets Boombah, a cast member of the Indian version of the children's TV show Sesame Street, called Galli Galli Sim Sim Photograph: David Guttenfelder/AFP/Getty

2007: Sesame Street characters Prairie Dawn and Zoe attend a portrait session for the You Vote Campaign at 1100 6th Ave in New York City Photograph: Jemal Countess/WireImage/Getty Images

2007: Two of the four new characters of Jalan Sesama, the Indonesian version of Sesame Street, Momon (L) and Putri during a ceremony in Jakarta Photograph: Bay Ismoyo/AFP

2009: Michelle Obama visits the Sesame Street set for a taping of a Public Service Announcement with Elmo as part of Sesame Workshop's Healthy Habits For Life initiative Photograph: Richard Termine/AP

2009: Zoe, Oscar the Grouch, Cookie Monster. New York City proclaims 10 November as Sesame Street Day to celebrate the show's 40th anniversary Photograph: Alex Oliveira/Rex Features