alt Hacker NewsThe treadmills at my gym have a big display with YouTube. Each time I run for ~1 hour and watch one of those Walking Tour videos.
It's much easier to run with something to distract you from the pain of running. Time really flies by.
Tokyo is a great pick for this kind of thing. It's big, so I usually pick a specific neighborhood (Hiroo, Shibuya...).
I did this for about 6 months but with marathons from around the world. I watched so many I started recognizing people! They get a little boring after a while so I stopped but it was cool seeing different cities and marathon routes.