This is current logo of Wikipedia. It’s like a jigsaw puzzle arranged in the shape of a 3D globe and each of the puzzle pieces contain a symbol that represents some language or character set.

Wikipedia Logo

The font used in the Wikipedia logo is Linux Libertine which is both open source and free.

Wikipedia Logo – Flat Form

If you were to flatten the Wikipedia logo, it will look something like this. See wikipedia.org/Wikipedia_logos to learn more about their puzzle logo.

Wikipedia Logo - Flat