It was a mild November night. And in Berlin something unbelievable was happening.

Hundreds, and then thousands, of incredulous East Germans surged towards what was once an impassable divide and found they could cross it unchallenged.

Later, crowds cheered as young men with pick axes chipped away at the concrete that had separated them from the West for decades.

As they sang and lit candles, reporters, stiff in their overcoats, spoke into the cameras.

The Iron Curtain had parted. The Berlin Wall was falling. One of the defining moments of the 20th Century was underway.

And Angela Merkel went for her weekly sauna.

“It was Thursday,” she said many years later, “and Thursday was my sauna day so that’s where I went.”

Merkel did eventually venture to the West that night - and back again the following day - but she was in no rush.

“I figured if the Wall had opened it was hardly going to close again.”

The response was typical of the young quantum chemist. And her approach – unhurried analysis in the face of high drama – is one with which the whole world has become familiar.