Movie: Rem Koolhaas explains how his preoccupations have shifted from urbanism and the city to preservation and the countryside in this second movie filmed by Dezeen at the launch of OMA's new Rotterdam skyscraper. "It's a cliche that everybody is living in the city," the architect says. Update: this interview is featured in Dezeen Book of Interviews, which is on sale now for £12.

The OMA founder believes that rapid urbanisation coupled with the increasing difficulty of building in heritage areas is creating a dichotomy for architects.

"We discovered that, unbeknown to us, a large part of the world's service is under a particular regime of preservation and therefore cannot be changed," he says. "That made us suddenly aware that the world is now divided into areas that change extremely quickly and areas that cannot change."

With most architects increasingly concerned with urbanisation, Koolhaas explains why he sees the countryside as an opportunity for OMA."It's a cliche that everybody is living in the city," he says. "Currently we are thinking about the countryside and what one could do in the countryside, and perhaps a new thinking about the countryside."

Besides his architectural work with OMA, Koolhaas also heads a sister organisation called AMO, which conducts research and gathers intelligence that feeds into both his and his clients' projects.

"We work as architects but also constantly try to explore where brand new issues arise or where new contradictions emerge, or where a particular way of thinking about a subject is no longer really kind of vital and needs revision," he explains.

Koolhaas explored some of these ideas at the OMA/Progress exhibition, which took place at the Barbican Art Gallery in 2011. One wall of the exhibition featured a series of images depicting countryside scenes in various European countries, while a previously sealed entrance was opened up for the first time in the gallery's history to highlight OMA's interest in preservation.