WASHINGTON ? The legendary educational puppet program "Sesame Street," home of Big Bird and Elmo, celebrated its 40th anniversary Tuesday as the longest running children's show on US television.

The famously playful puppets, who taught generations of children the basics of reading, writing and counting, first appeared on public television in November 1969, and celebrated their birthday with a guest appearance from First Lady Michelle Obama.

To mark the occasion, Obama explained to young viewers how to cultivate a home garden, including tips on growing tomatoes, cucumbers, and carrots.

Many of the characters, which also included Bert and Ernie and the Cookie Monster sprung from the creative well that was Jim Henson, father of the equally legendary "Muppet Show."

Aimed at children aged two to six, the series has earned 122 Emmy awards, the small screen equivalent of the Oscars.

The street has also become an international phenomena for children's television, running all the way through 140 countries around the world.

On the show, which broadcaster PBS says is where children can "use their imaginations, build social skills, and respect people's differences," audiences have reveled in the antics of a fictional New York street where "multiethnic, multigenerational, and even multispecies residents coexist in harmony."

This year's season, said the Public Broadcasting Service, focuses on a new nature-focused curriculum aimed at fostering "a love and understanding of the natural world."

Co-founder Joan Ganz Cooney said she was inspired to create the show for communities that could not prepare youngsters for the education system.

"Our original goal was simple: to create a successful television program that would make a difference in the lives of children, in particular, poor inner-city children, and help prepare them for school," she said in a statement on PBS.