Yesterday I crossed the river walking over the Eleanor Schonell Bridge. On the news was a story of a bridge being swept away by floodwaters in England. To remain safe over a long period of time, bridges have to be carefully over-built since natural systems tend to pushback against the intrusion. While bridges are generally static (with the occasional human maintenance), trees can respond by growing. This feedback, as opposed to resisting pushback, is evident on the eastern side of the bridge where a old fig tree has progressively grown  aerial roots to support itself. We need bridges that can grow an extra pylon or two as demands or the environment change.