Look around Tokyo and you can still see the concrete legacy left by the 1964 Olympics and the subsequent economic "miracle." Wood can change that, says the architect of the main stadium for the 2020 Games.

Using Japanese lumber for the centerpiece venue, Kengo Kuma wants to restore woods that Tokyo lost half a century ago in the blitz to build highways, bullet trains and skyscrapers to showcase the recovery from wartime devastation.

The design stems from his "natural architecture" concept of making buildings part of the landscape.