OMG, after looking at this old picture I spotted the "Hippy Tree"
There was a picnic table under this tree, and if you were cool, and hip, you sat there. I remember playing my guitar and everyone loving it and we use to play our portable record players, holding hands, lol sometimes sneaking a kiss or two. We were the closest thing to a hippy who was there in the late 1960's. Now we can put this to rest, the Hippy Tree has been found.
Note the sidewalk, next to Hippy Tree, under this sidewalk was the "Tunnel". In the winter snow was always melted from the sidewalk due to the hot steam in the tunnel

click image for a full-sized view