I had a fun time thinking of internationally-acclaimed iconic designs. Olympic rings. Recycling arrows. Skull and crossbones, even? http://upload.wikimedia.org/wikipedia/en/b/b1/Olympic_Rings.... http://upload.wikimedia.org/wikipedia/commons/4/44/Recycle00... Guess .svg isn't embeddable.
The two that come to my mind: Thing one, because it's such a loaded symbol. It means such different things to different people. For some it's a symbol of hate and oppression and dehumanization, while for others it's a source of pride. And thing two, because it's three goddam circles. How in the name of Christ is that a mouse? It isn't, but we can recognize it as such immediately. Both trip me out.
The Coca-Cola script is one that comes to my mind. And the Nike swoosh. Both are international and instantly recognizable.