Tuesday and Thursday mornings I walk across Madrid to my French class and then back home again. Since my house and the academy are more or less on opposite sides of what is "central Madrid" the walk takes me about 40 minutes and covers a little less than 2.5 miles each way. I started walking because there is really just one bus that would take me there and the metro connections aren't great. Plus the walk is really nice - especially in the morning (8:30ish) when the temperature is still manageable. The first part of the way - across the Retiro - is the perfect way to wake up because of the quietness and relative solitude (in the midst of a City of 4 million crossing paths with perhaps 20 people in 15 minutes is pretty quiet).
After the park I head down two of the major Madrid streets - Alcalá and Gran Vía - passing a decent cross-section of the Madrid population. As I do I wonder how many of those people are "walkers" like me and how many are simply on their way to a mass-transit stop. I definitely appreciate the massive bus and metro networks that cross Madrid and I take advantage of them on a fairly daily basis. But I am also appreciative of what a walkable city Madrid really is, at least from where I live. There is an old saying in St. Louis that you are 20 minutes from everywhere. For Madrid I'd change that to 30 minutes; in about half an hour I can get - on foot - to just about anywhere I want to go.