Haus der Kulturen der Welt

Listen first. Water moves softly in the long pool in front of you. Somewhere behind the trees, traffic hums along the edge of the Tiergarten, Berlin's great central park. Then you look up, and a vast white roof seems to float above a wall of glass. It curves upward at both ends, like a shell opening toward the sky. Welcome to the Haus der Kulturen der Welt, the House of the World's Cultures.

Berliners have a nickname for this building, and once you hear it, you cannot forget it. They call it the pregnant oyster. Look at the shape again, the low swelling body and the two raised lips of the roof, and you will see why. The name began as a joke. Over the decades it has turned into something closer to affection, and many locals still use it more often than the official title.

The building did not begin as a house of world cultures. It opened in 1957 as the Congress Hall, a gift from the United States to West Berlin. That was the year of Interbau, a major international building exhibition. Architects from many countries came to show what a modern, democratic city might look like after the destruction of the Second World War. The American contribution was this hall, designed by the architect Hugh Stubbins.

Think about the moment. Berlin was a divided city in the middle of the Cold War. The border between the Soviet sector and the western sectors ran very close to here. The Berlin Wall did not exist yet, but the tension did. So this hall was more than a meeting place. It was a statement about open debate, free speech and the friendship between America and West Berlin, placed where people on the other side could see it.

Now look closely at how the roof works, because it is the heart of the design. The great curved shell is a saddle shape. It dips in the middle and lifts at the edges. Two sweeping arches carry its weight down to the ground. Underneath, the auditorium sits on a raised platform, so the roof seems to hover. For the 1950s, this was daring engineering. It was meant to look light, almost weightless, and confident about the future.

Here is the part of the story many visitors miss. In 1980, part of that daring roof collapsed. A section of the outer shell came down without warning, and one person was killed. Investigations pointed to corrosion and stress in the structure that had built up over the years. For a building that stood for optimism, it was a painful blow. For a time, many people wondered whether the oyster would ever open again.

It did. The hall was rebuilt and reopened in 1987, the year Berlin celebrated its 750th anniversary. The new roof keeps the original silhouette, so from the outside the building looks much as Stubbins imagined it. Two years later, in 1989, it took on a new life as the Haus der Kulturen der Welt. That same year, of course, the Wall fell. The building's new role and the city's new chapter began almost together.

So what happens inside today? This is a centre for contemporary art and ideas, with a strong focus on cultures from beyond Europe. Over the years it has hosted exhibitions, concerts, film screenings, lectures and long evenings of discussion. The programme often asks difficult questions about history, migration, ecology and power. It looks at the world through many eyes, not only a western one. In a way, it continues the old purpose of the Congress Hall. It is still a place for open conversation.

Turn back toward the pool. Rising from the water is a large bronze sculpture by the British artist Henry Moore. Its title is Large Divided Oval: Butterfly. It is a smooth form with two curving wings that seem to lean toward each other without quite touching. Notice how its curves answer the curves of the roof behind it. Walk slowly along the edge of the pool and watch the sculpture change shape as your angle shifts.

The reflecting pool is part of the experience, too. On a calm day the water mirrors the white roof and the sky, and the whole building seems to double. On a windy day, the reflection breaks into moving pieces of light. Photographers like to crouch low near the water's edge here. From that position the roof, the sculpture and their reflections line up into one long, layered picture.

Now look a little way off to the side, and you may see a tall dark tower standing alone among the trees. This is the carillon, a bell tower built in the late 1980s. A carillon is an instrument of many tuned bells, played by a musician at a keyboard high inside the tower. It is one of the largest in Europe. At certain times a player gives concerts, and the music drifts across the park and the river in a way no recording can copy.

Step back once more and take in the neighbourhood. The river Spree runs just behind the building. The Reichstag, home of the German parliament, with its glass dome, stands nearby, along with the modern government buildings of the Chancellery. Once this area sat near the edge of a divided city. Today it is the centre of government in a united Germany. The oyster has watched that entire change happen from this same spot.

Before you move on, pause by the water for a moment. Look at the edges of the roof where they lift toward the sky. Listen to the park, the river and the voices of people coming and going through the glass doors. This building has been a gift, a symbol, a ruin and a meeting place for the world. As you walk away, glance back once. From a distance, the white shell still seems to float, just as it was meant to.