20 Rare Behind-The-Scenes Pictures From The Early Years Of "Sesame Street"

Cast members and puppeteers prepare for a taping of Sesame Street in 1969.

Puppeteer Jim Henson holds Bert and amuses a baby during rehearsal for an episode of Sesame Street in 1970.

Left: Kermit the Frog during rehearsals in 1970. Right: Puppeteers Frank Oz (left) and Jim Henson (right) rehearse in 1970.

A television camera and lights focus on Grover, 1970.

Puppeteers Jim Henson (left) and Caroly Wilcox (right) rehearse in 1970.

Left: Puppeteer Caroll Spinney with Oscar the Grouch during rehearsals in 1970. Oscar was orange in the first season. Right: Muppet Professor Hastings being filmed in 1970.

From left: Puppeteers Daniel Seagren and Jim Henson with the Ernie puppet and Frank Oz with Bert rehearse on set, 1970.

Actor and singer Bob McGrath rehearses for an episode of Sesame Street, 1970.

Puppeteer Caroll Spinney has an adjustment made in his Big Bird costume during rehearsal, 1970.

Right: Puppeteers Daniel Seagren (left) holding Roosevelt Franklin, Jim Henson (center) holding Grandmother Happy, and Frank Oz (obscured by camera) holding Betty Lou during a taping of a Sesame Street episode, 1970. Right: Actor Loretta Long with Big Bird on set, 1970.

Big Bird and actor Loretta Long during the filming of an episode of Sesame Street in 1970.

From left: Research director Edward Palmer, executive producer David Connell, and executive director and producer Joan Ganz Cooney review material for Sesame Street at the PBS station in New York City, 1969.

Children watch an episode of Sesame Street at the Margery Reed Mayo daycare center in Denver, 1969.

Puppeteer Jim Henson holds Kermit the Frog and entertains children during rehearsals, 1970.

Jim Henson holds Kermit and amuses children during rehearsal, 1970.

Ernie, Bert, and other Muppets backstage during rehearsals, 1970.