World's Longest Bridges

Part of my Nigerian adventure included crossing (twice!) what I was told was Africa's longest bridge - from the airport to Lagos Island (and onto Victoria Island, which I presume is part of Lagos, but what do I know - clearly I need to improve my knowledge of Nigerian geography...)

Anyway, that got me wondering - what's the longest bridge on each continent? And I wonder if someone's crossed all of them? The first question was pretty easy to answer, thank you Wikipedia... I thought Lake Ponchartrain would be the longest, but am amazed it's nearly 4 times the Third Mainland Bridge (which is what I assume is the bridge I crossed in Nigeria, not that there were any signs or anything!) I'm glad I'm only reading *now* the fact that it may be in urgent need for repair, as the government has not maintained it in 15+ years (according to Wikipedia, that is).

A bit harder to answer the 2nd question - if anyone's crossed all of them. I'd say perhaps the Bridgemeister, however it seems he concentrates on suspension bridges (with a few exceptions, yes)... I'll have to keep looking. Perhaps the Bridgetravelmeister is around here somewhere!