Apart from the giant yellow bird, the red furry monster and the blue Muppet with an insatiable appetite for cookies, “Sesame Street” appears as real as the New York City streets that inspired it.

This first episode of “Sesame Street” — sponsored by the letters W, S and E and the numbers 2 and 3 — aired in the fall of 1969. It was a turbulent time in America, rocked by the Vietnam War and raw ...