Today the boys woke up with what seemed to be more energy than normal, so after lunch we decided to start walking La coulée verte (walking trail that runs from Massy to Paris) and see how far we could get.  We saw things from a wonderful, new perspective.  On the train we see bits and pieces of the cities we pass to get to Paris, but today we walked through parks in the different cities, played on playground equipment along the path, saw a fun Greek wedding reception and were stunned when we saw a beautiful château (Château de Sceaux) surrounded by manicured lawns and flowing fountains.  After about 7 km on the path and about 2-3 km more off the path with light rain falling, we decided to call it a day and found a nearby bus stop to ride to the nearest train station.