I'm afraid what we are building today will not have the same impact and sustainability of the architecture of a 100, 500 or 1,000 years ago. The buildings of those days were miracles. We don't perform such miracles today. So we should be a little more modest. For my part, I'll be glad to show one of my buildings one day to my grandchildren and say: I'm proud of that.

Isolation means a lack of growth. I grew up in China at a time when the country was completely isolated. That era is over.

I am a runner. Last October, there was a marathon here in Beijing. I didn't participate this time, but friends told me that the run wasn't prepared too well. The organizers had only arranged about three hours' worth of food and water supplies. Most people don't finish within three hours, however. Too bad for them - or so it seemed. In fact, however, even those finishing last were perfectly taken care of, particularly during the fourth and fifth hour when demand is highest.

Our tenants now are companies like Uber, the taxi service, Meituan.com, China's version of Groupon - and a large number of startups. These companies operate in a modern way, just like their customers: They go on the Internet, look for an offer and take it.

China's economy became more complex. By now there is a large number of small- and medium-sized companies that work quite differently from big, state-owned enterprises. They don't follow any long-term business plan and don't rent office space for years to come. They start out and need an office right away, for a week, a month or half a year, and they want to be among other entrepreneurs like themselves.

Because people along the route had realized that there was demand and quickly organized supply. That's so Chinese. In a well-organized country like Germany, such a problem may not have arisen in the first place, but in China people immediately recognized an opportunity.

Growth will be slower, no one denies that. But the question is: Where are the chances and opportunities now? I see some positive and some negative trends.