TED is over and I am already in withdrawal. There's a well-documented reaction called TEDcrash that can accompany re-entry into normal life after four days of immersion in amazing ideas and even more amazing people. I have met more than 90 people in the last five days; each conversation has been at the very least interesting, and at most completely mind-blowing.Here's a summary of the two sessions from this last Friday morning:Session 11: Cities Past and FutureEric Sanderson gave one of TED's most beautiful sessions on the Mannahatta project, which has mapped and cross-referenced every geographical feature and species of flora and fauna of Mannhattan going back to 1600 and culminating in a gorgeous virtual reality view; Constanza Cerruti showed the value of archaeology at high altitude (over 6,000m high!); Carolyn Steel was inspiring, forthright and downright fascinating on how cities were shaped by their food supplies up to the rail and road revolution and how important it is to reforge that broken relationship now; Bjarke Ingels was totally inspiring and al