Is there a mailbox in zork i

A blast from the past!

Yes, there is a mailbox in Zork I. In fact, it's a rather famous one. In the Great Underground Empire, you can find a mailbox in the Grail Castle, which is located in the northwestern part of the map. The mailbox is labeled "Post Office" and contains a cryptic message that reads:

"Dear Adventurer,

You are not the first to seek the Grail. Many have come before you, and many have failed. But you may yet succeed, if you can answer the riddle of the Post Office.

What is the answer to the riddle of the Post Office?

Sincerely, The Postmaster"

Solving the riddle of the Post Office is a crucial part of the game, as it helps you progress further in your quest for the Grail.