The NounProject is devoted to collect and express the most recognizable symbols of different societies in a visual way through free icons.
The Noun Project states that they are on a mission
“sharing, celebrating and enhancing the world’s visual language”
The content has been translated to 24 languages so you can find icons in your own vernacular language. Icons are properly categorized and tagged and you can even search for a particular term.
Sweden designer Viktor Hertz already put these icons to good use and created these cool pictogram posters
Check the icon license before downloading and using it, because while some are in the public domain like this downhill skiing icon, others are licensed under CreativeCommons Attribution, like this teapot.