Join Grover, Big Bird, and the rest of your friends from Sesame Street on a trip to the post office. Learn how to send letters and packages, what postal workers do, how mail gets to where it needs to go, and more! About the Sesame Street ® Field Trips series: Discover some of the amazing places in our communities—from the post office to the zoo—with the help of friends from Sesame Street . Hands-on back-matter activities help children engage with what they've read.