Who doesn't love collecting stamps? The art and science of stamp collecting is called philately!
The first stamp was used in the UK on May 6, 1840. Queen Victoria's profile was used as the image and is one of the most recognized images in the world. The first stamps used in the US were images of George Washington and Benjamin Franklin, each worth five cents. Throughout the years, stamps have come in all sorts of themes including nature, scientists, comics, culture, sports, and even stamps on stamps!
Although technology now allows us to 'mail' someone instantly via gmail, yahoo, hotmail, AOL, etc., sending a letter through the physical mail and waiting your three-ish days is still nostalgic. This container is something letter carriers used a lot back in the day. The massive containter is a letter carrier drop point, where mail persons could pick up bulk mail to deliver around the neighborhood, kind of like a mail system within a mail system. Don't try to open this unit, you can't. These are sealed off containers and designed only to be opened with a mail deliverer key.
For more information https://postalmuseum.si.edu/