The World Bank continues to be one of the leaders in open data and the visualization of that data. I recently came upon the World Bank eAtlas. It takes the data made available and maps the indicators in order to compare countries around the world.
In the screen grab above, I searched for the average age at first marriage for women. The user can hover over each of the countries to see the specific data. On the right, suggested categories that are related to the topic, such as the percentage of women who are beaten by their husbands when caught burning food, are displayed.
Users can also use the tools to see MDG progress, financial inclusion, and global development, in addition to gender as already seen. For a data nerd this is a resource that is definitely worth checking out and clicking around.