Frankfurt Germany - Wandering in another direction

I had this idea after the great Saturday that I would rent a bike and zoom the day away around Frankfurt on Sunday - it turned out to be a grey, cold and rainy day.  Wandered a bit but it was just an ugly day.
We had a beautiful spring morning before we caught the train to Paris on Tuesday.
I wandered around the City a bit more but then hit the trail along the river.  Just like home the trail was filled with runners, walkers, biker and plenty ducks and geese that let everyone know where their space begins and ends.  An aggressive group of birds.
Lovely metro of about 2.5M people - financial center of Germany.  I kept passing tourist style buses as I wandered and as I headed back to the hotel caught the beginning of a "large" protest march - why I saw buses from all over Europe.
And were in a very cool spot for our event as well the day before.