Everyone asks me this. On some level there are many cities in which I could conduct this research. But there are some interesting parallels to be made between Boston and Helsinki.
First, they are more or less the same age, which is rare when comparing North American and European cities. (Boston was founded in 1630, and Helsinki—depending on whether you include the first settlement to the north, is either 1550 or 1640.) The cities themselves are roughly the same population, although Boston’s metropolitan area is much larger. And Boston and Helsinki are both port cities that look to their harbors for trade, communication, and defense. Both have been governed from afar, and both have sought—and won—home rule. They each have epic stories that permeate the culture and local heritage—for Boston the American Revolution and for Helsinki the Kalevala. And they are both capitals, one state and one federal. Each of these commonalities help Boston and Helsinki start out from a similar place, but then one can quickly see that they have developed into very different cities, which makes for an interesting study.