On November 10, First Lady Michelle Obama and Broadway star Lin-Manuel Miranda dropped by the set of Sesame Street to help the cast celebrate the show's 40 years of teaching kids ABCs, numbers and daily life lessons, USA Today reports.

While it premiered in the United States, the show is now available in 120 countries and territories around the globe. South Africa's version of the program, called Takalani Sesame, introduced an HIV-positive Muppet named Kami in 2002 to address the country's mounting AIDS epidemic and teach young viewers about the virus in a child-appropriate manner to combat stigma.

The show's socially progressive slant is also apparent in the U.S. version of the show. While Sesame Street has yet to introduce an HIV-positive Muppet domestically, a human character named Gina adopted a baby and became a single mother in 2006. Such decisions have often been met with criticism from some viewers.

“We get letters all the time,” said Sesame Workshop's vice president of education and research Rosemarie Truglio. “My response is always this: Sesame Street is this wonderful multicultural place where we celebrate differences as well as similarities.”