Kiyotsu Gorge is a great place for photos! Renovated by MAD Architects, this "Tunnel of Light" offers a great views of the canyon through a couple of different tunnels including a reflective pool a more artsy style tunnel. Both are fun to see and peer out of for the views of the gorge.
If you want to refresh a little after the walk, go into the cafe and you'll find a foot onsen on the second floor.
Oh! Check out the toilet! I will let you discover what I mean. I don't want to spoil it for you :)