Recently, my wife and I visited London and Paris to see friends and get a change of scenery, leaving behind for a bit the New York that we love.

As we spent a wonderful two weeks exploring these beautiful cities, comparisons between our three favorite cities began to ricochet in my head. Then, mere hours after we departed Paris, ISIS did the nearly unimaginable, and once again attacked the French capital.

While I had already spent much of the week thinking about what made New York, Paris, and London special, the terrorist attacks helped crystalize my thinking.

All three cities have different cultures and charms, but they all have one thing in common: they have shown the rest of the world the power of diversity, rationality, and beauty.

Attacking such metropolises furthers terrorist goals by making headlines and causing pain on a national scale, but at the root of what attracts radicals to attack these cities is what they stand for.

London is a practical city (except for the decision to drive on the wrong side of the road). It is a hub of global business and finance. And after the 2005 London bombings, the English responded pragmatically, with a focus on getting back to “business as usual.”

New York is an ambitious, multi-cultural center, and our response to 9/11 showcased our commitment to those qualities. After 9/11, New York rose up and came together. We unified, rebuilt, and took action.

Paris is a warm city, architecturally and culturally. It is famously a city of light and of love. On Friday, darkness fell in that beautiful city, but the French will show that no carnage, and no violence can snuff out the love at the heart of their way of life.

All three cities demonstrate the power and allure of our secular, cosmopolitan freedoms, and all stand as a finger in the eye of hateful, zealous, religious extremists across the world.