I loved the Rem Koolhaas book Delirious New York, but I happened to be in Seattle in 2004 the week the Central Library he designed opened and I wasn’t really enamored of it the way I am many of his other works. It has an impressive exterior, but the interior felt like it was meant more to be looked at than utilized, though I guess that is the epitome of the modern library in a portable world, the best-case scenario, even–perhaps people will at least take a glance.

As his Fondazione Prada is set to open in Milan this month in a repurposed, century-old industrial space, the architect has become more focused on revitalization and preservation rather than outré original visions. From a Spiegel Q&A with him conducted by Marianne Wellershoff:

Kultur Spiegel:

Does a building need to have a certain age or degree of prominence for us to recognize it as important?

Rem Koolhaas:

The idea of preservation dates back to the beginning of the modern age. During the 19th century, people essentially felt that something had to be at least 2,000 years old to be worthy of preservation. Today, we already decide during the planning stages how long a building should exist. At first, historical monuments were deemed worthy of preservation, then their surroundings, then city districts and finally large expanses of space. In Switzerland the entire Rhaetian Railway has been added to the list of UNESCO World Heritage Sites. The dimensions and repertoire of what is worthy of preserving have expanded dramatically.

Kultur Spiegel:

Were there structures in recent years that you think should have been better preserved?

Rem Koolhaas:

The Berlin Wall, for example. Only a few sections remain, because no one knew at the time how to deal with this monument. I find that regrettable.

Kultur Spiegel:

And what do you think of the concrete architecture of the 1960s, a style known as brutalism? Should it be protected or torn down?

Rem Koolhaas:

We should preserve some of it. It would be madness for an entire period of architectural history — that had a major influence on cities around the world — to disappear simply because we suddenly find the style ugly. This brings up a fundamental question: Are we preserving architecture or history?

Kultur Spiegel:

What is your answer?

Rem Koolhaas:

We have to preserve history.•