I'm scared of bridges.
Not all bridges - I'm fine on footbridges over water. The type of bridges I'm scared of are bridges where there are lanes of traffic running next to the pedestrian path or even worse, foot bridges over busy roads. Perhaps its traffic that I'm scared of, although I'm not that keen on bridges over railway lines either but I can just about manage those without vomiting.
In Prague, we went the wrong way back to our hotel one night and ended up walking along the side of a dual carriageway, right next to the traffic which also involved a bridge over yet more traffic. I was terrified. I didn't fair much better walking across Brooklyn Bridge. There is a lot of camera shake on my photographs - it doesn't look artistic, just a reminder of my horror.
Last night I went to Ikea. The quickest way to get there from the tube station involves firstly a bridge over a railway line (with traffic running alongside) and then crossing a bridge over umpteen lanes of rush hour traffic. I had to cross the railyway bridge - there wasn't much alternative. My palms were soaked by the time I got over it. I had every intention of facing my fear of the bridge over traffic but I was too shaken by the first bridge that I backed out. This added about another 15 minutes onto my journey time and I was very disappointed with myself.
A pedestrian bridge over a busy road just outside of my home town once collapsed - I don't think anyone was hurt but it has stayed with me so may be at the root of my fear. There were some lovely window boxes in Ikea that I didn't buy last night so I'll probably be going back there soon and perhaps next time I will manage to cross that bridge.