Forest, Belgium

With a population density of over 23,000 people per square mile, Forest is a tightly packed urban center that offers little in the way of open space or tranquility. The municipality's 56,581 residents are crammed into just 6.29 square kilometers, making it one of the most densely populated areas in Belgium. And while the historic abbey and art deco architecture provide cultural attractions, the constant bureaucratic headaches and lack of green spaces are a persistent challenge for residents.

Those seeking a more serene, suburban lifestyle would do better to look elsewhere. Forest is a no-frills, high-density city best suited for young professionals and those drawn to its vibrant arts scene and central location within the Brussels-Capital Region.