Another week, another flash of terrorism in my city, this one, thankfully, thwarted by the British security services. As usual, the headlines hit me on my doorstep. Islamic terrorists have worshipped at the Finsbury Park mosque, a 10-minute walk from my home. Two of those arrested last week live in my neighborhood, Stoke Newington.

On Friday, to escape my unquiet thoughts, I put my 1-year-old daughter in her stroller and walked into the park that is literally outside my door. In a world slowly splitting at the seams, Clissold Park is like a dream.

Huge families of Hasidic Jews, in their unseasonably hot, traditional dress, stand along the railings feeding the ducks, geese and squawking moorhens who nest on the willow-draped island in the middle of the pond. Next to them, equally vast families of South Asian Muslims, the women in unseasonably hot hijab and long skirts and occasionally full burkas, are doing the same. The kids run along the railings, intermingling if not actually engaging with one another.

I push my baby toward the park's playground and close my eyes for a moment. These are the languages I hear: Turkish, Urdu, Arabic, Yiddish, Polish, Russian, Greek, Somali, Amharic and other African languages I cannot name. On Sundays, Spanish and Portuguese are added to the mix as groups from other parts of town turn up to play soccer.

There are all varieties of English, too. Stoke Newington has been thoroughly gentrified in the past decade, and now you hear cut-glass accents that used to exist only in Kensington and Chelsea along with working-class diphthongs and glottal stops from the local housing projects.

What makes this worth commenting on is that within Clissold Park, some of the most intractable conflicts in the world seem to have been resolved — or at least temporarily ignored. Kurds and Turks, Jews and Muslims, working-class and middle-class people (this is Britain) all coexist, enjoying the lawns, the deer park, the ponds, the rose garden and the wading pool.

Some of this is possible because of bedrock British custom. For example, queuing. There are only four swings, far too few for the number of kids who use them (another British tradition, not providing adequate public facilities). But parents take care to wait their turn. The Hasidic Jew nods to the woman in hijab, and the exchange of swings takes place, with none of the coiled resentment I have seen in American playgrounds.

When I first moved to the area in 1989, the park did not have anything like the variety of ethnicities and nationalities using it. What has happened in London since then is possibly the most remarkable peacetime change in the ethnic composition of a European city. Without warning and by increment, a vast influx of people from around the world has changed the city into something like the idealized, happily multiethnic, liberal New York of my childhood.

That's not to say it's all Elysium around here. There have been hate crimes; the local mosque was attended by Richard Reid, the so-called shoe-bomber, and Zacarias Moussaoui. But whenever the hate and violence threatened to boil over, leaders from all faiths spoke out, calling for peace, and the tensions cooled.

Still, as I watch my daughter and listen to the din of a dozen languages, I feel an end-of-summer sadness. Someday soon, someone with an inability to value what is precious about Clissold Park will commit the act that shatters this small world and drives all of us into our corners. Before that happens, I want my daughter to know that there was an alternative.

Michael Goldfarb is the author of "Ahmad's War, Ahmad's Peace: Surviving Under Saddam, Dying in the New Iraq." He wrote this commentary for The New York Times.