In this next movie from our series filmed at the OMA/Progress exhibition at the Barbican in London, OMA partner Reinier de Graaf talks about the Dutch architecture studio's preoccupation with the megacity and its hinterland  - "the vacuum left in the wake of the city's expansion." He suggests that we're moving to an era of city states and this is leading to a potential new relevance for architects as civic leaders.

Reinier de Graaf talks about more of the firm's preoccupations, including the nature of London, in our earlier movie.