Via Andrew Sullivan, here's a clever interactive map from Mother Jones that color-codes countries by the number of U.S. troops stationed there. The scroll bar allows you to see how levels have changed over time since 1950 in five-year increments. You can watch the troop presence in Vietnam gradually increase over the course of 20 years before disappearing completely, or see the military's several arrivals and departures from Iraq over the last half century. You can also click on a country to get more details.