It's never good news when a teacher calls. It usually spells sickness, injury or trouble. But yesterday was a first. When my phone rang yesterday, it was my daughter's kindergarten telling me the building had been evacuated after the discovery of a World War II bomb on a construction site at the neighboring school. A couple of minutes later, I got two emails from said school. It's where my other kids go.

The voice of reason assuring me there was little likelihood of real danger, I wouldn't say I moved down the office stairs at breakneck speed, but once I was on my bike and headed toward the suspicious object, I noticed I was cycling with more vim than normal.

Perhaps it's because I like a busy narrative, but as I went, the streets I passed down morphed into ghosts of their gentrified selves — into those unforgettable 1945 images of some of the city's half million or so apartments devoid of roofs, walls and life after being pounded to bits by the Allies during the final throes of the war.

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As I cycled, my pedals turning in time with the increasingly willful pace of my imagination, the growl of a hovering storm cracked through the solid summer sky, creeping neatly into the story playing out in my mind. I no longer just saw the husks of homes, but heard, in the thunder above me, the rumble of artillery.

And somewhere in and amongst it all, I thought about the 3,000 bombs said still to be slumbering in Berlin's sandy soil, most often hit upon during building work. Of the mass evacuations they prompt across the city, of recently reading how over time, their corrosion makes them evermore dangerous, and of the debate about whether the federal or state government should stump up the money for their removal.

Rounding a corner into my Kiez, which is a slang word for immediate neighborhood, I saw an old hollow-cheeked lady perched on the seat of her walking frame.

It occurred to me that she might have seen or heard some of the 100,000 tons of allied bombs and phosphorus munitions drop on the city more than 70 years ago. Perhaps even the one toward which I was heading.

'Our house could go kaboom'

When I reached the street where the kindergarten (and my house) is located, it was blocked by police cars at either end. I was allowed into the gardens, where a group of small children — some of them decidedly teary-eyed at having to leave their beloved stuffed animals in the off-limits building — sat quietly huddled together. I took my daughter's hand and as we set off — animal-less — to find her sisters, she worried aloud about their safety and the possibility of our house going "kaboom."

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By the time we located my other girls, the whirrings of my worst-case scenarios had been stilled both by the modest official presence at the scene, and by a policeman who told me in characteristically understated Berlin fashion that the mysterious find was "just a little something from World War II." But the children's imaginations — being even livelier than mine — wanted solid assurance that nobody and nothing was going to come to any harm.

In the event, it came quickly. An hour after the initial alarm bells had been sounded, the bomb, grenade or whatever it was had been taken away. That was that, end of story. Except it's not. On the way back to kindergarten today, my littlest daughter said she hoped there wouldn't be another bomb. When I told her it was unlikely, she said, "but not impossible." How right she is. My phone is switched on.

In Berlin and Beyond, British-born Tamsin Walker takes a closer look at some of the quirks and perks of life in Germany, which has been her home for almost 20 years. She tweets as @TamsinkateW