Not all children have equal access to educational materials. Some start music classes in early infancy or begin learning a second language as a toddler, but millions of kids aren't so lucky. That said, any child who has access to a television should be able to watch Sesame Street, which appears on PBS. (Starting in 2016, the children's show began airing first on HBO, but it still reairs on public television.)
And that's a good thing: The benefits of watching Sesame Street have been rigorously researched in more than 1,000 studies over the course of 30 years. One study, published in 2015, found that "the TV show is 'the largest and least-costly [early childhood] intervention that's ever been implemented" in the United States, as Phillip Levine, the study co-author, told The Atlantic.