Migration flows are often difficult to visualize. Enter the Migration Policy Institute, which has created an interactive map that shows, to the nearest thousand, the latest number of immigrants and emigrants moving between countries. This new tool, which uses U.N. data, casts some interesting light on migration trends. For example, some nations send nearly equal amounts of migrants each other’s way – like the U.K. and Australia. Most have a preferred destination — like the Americans moving to Mexico in large numbers. And it seems Russians have had a longtime preference for Ukraine.