Things you must know about the world in three maps.

There is a great new site from The Washington Post with 40 maps, some of which are animated. Here are a couple that I found especially relevant:

Where the world's people live, by economic status

Those dots represent people: the brighter the dot, the more people. The color shows their country's average income level: blue is richest and yellow is poorest.

How countries compare on economic inequality

 Yes, the United States has worse income inequality than Nigeria. That's according to a metric called the Palma Ratio that measures economic inequality. Read more here about how the metric works and the fascinating results of using it to compare the world's countries.

 Where the world's 30 million slaves live

 This is not some soft, liberal, by-modern-standards definition of slavery. This is slavery. There are 30 million people living today as forced laborers, forced prostitutes, child soldiers, child brides in forced marriages or other forms of property. There are 60,000 right here in the United States – yes, really. This map shows the proportion of each country that is enslaved.