Observe the Mount Fuji from the Tokaido Shinkansen window.
Traveling to Kyoto or Osaka from Tokyo? Try to reserve a seat E, which is the right window side. If not you can always go to the space between cars to look out. It is only a brief moment, say 10 mins to catch the view. After departing Tokyo there will be many tunnels and that's when you have to pay attention. You might even want to use your google map to monitor where you are. There is an outlet if you are lucky enough to reserve window side.
On sunny clear winter days, you can see Mount Fuji that appear so close to you and it is just beautiful. You can believe that 70% of Japan is actually forests and not ugly concrete buildings.
I maybe biased since it is so programmed in my gene. Growing up in Yokohama means that I always had this view but it just never tires me.