Green Door in York

What's behind that green door?  It's so small too! Is there music? Can I come in? Oh, if we only had more time to explore the green door and York but we were on a schedule.  

We did, however, climb the stairs on Bootham Bar, looked out cross shaped holes that were made for weapons when the guards were guarding the city, walked the stone wall that surrounded the city.  We could look right into people's backyards from the wall.  I would really hate it if my house was next to a wall where people could look into my backyard.  Where's the privacy? One clever thing was that a lot of yards had steps up to the wall so maybe, the guards lived in those houses at one time and that was their way to go to work.  Bar was a gate and gate was a street - part of the Viking language.