I've updated this with newly found information*
In Munich we stumbled upon a beer garden called Augustiner-Keller. http://www.augustinerkeller.de/restaurant/der-lagerkeller/?L=1
We walked in and there were several open tables among the locals (Later discovered by looking at website that is "the Hall") and we thought they would seat us there. She didn't. She walked us to a back room that was empty. It was strange. (later determined to be the Festaal)
I got up shortly thereafter to see about sitting with the locals when i noticed a door....i motioned my wife to follow as it appeared to go to a "bar area" in the basement. (You can see a pic of the door to the "Lagerkeller" to the right in The Hall)
It was a spiral stair case down to the Lagerkeller. Very narrow. I followed it down and down and down. At the bottom was a closed door. I kind of panicked and started back up. Something made me stop and test the door. I was actually a bit scared.
Once the door opened, it was a massive underground bar. Lots of tables. We sat down, not many people were there. We had a drink with an Asian man. Turns out to be from Hawaii. His wife was the head of Hawaii tourism bureau and he followed her around the world and entertained himself while she was "working"
The place filled up. Asian guy left and unbelievably, the owner sat down with us. He bought us several rounds and shots.
He told us how beer gardens started. This room, which was massive, was used to store beer kegs in. They would fill it with kegs and snow during winter.
They then would have beer all summer. The ground above would be the "garden" that the beer would be served in. Usually under shade trees.
It was awesome.
He finally had to go back to work and we head upstairs to The Hall. We decide to have a beer with the locals. (In the pic on the website, you can see the beer barrel tables on the left. That's where we end up sitting with the German man mentioned below)
One man started chatting with us. A strapping man. Blonde hair, blue eyes. Probably in his 70's but well maintained. Despite the language barrier we had a wonderful time over several beverages.
I regretfully made him cry when i asked about Hitler etc. He admitted to being a "Hitler Youth". He said he was not old enough to know what was going on at the time. I didn't know if i believed him but he seemed sincere.
It was an amazing evening.