It was once the case that a beer city happened to be adjacent to a big national brewery (we're looking at you, St. Louis). But as we all know, the American beer-scape has changed in the last 30 years. Today, there are more than 4,000 craft breweries in the U.S., and most of them are microbreweries — small enough to squeeze into the confined space of a city. So if you want to drink the best beers in the world, head downtown — to San Diego, Philadelphia, Portland, and Milwaukee. The following is a list of cities with beer scenes spearheaded by people who passionately care about brewing and who serve the finest beers in the world. Some towns are more brewery-centric, while others are more intimately connected with the international beer world. But they all take beer to another level, and they all deserve to be on your travel wish list.