Sydney Harbour Bridge

Look at those four massive granite pylons at each corner of the bridge. They look absolutely essential, right? Structural, load-bearing, holding the whole thing up. They do nothing. Zero structural load. The arch handles everything. The pylons were added because engineers worried the public would not feel safe crossing a bridge held up by what looks like thin air. They are the world's most expensive security blankets.

The opening ceremony in nineteen thirty-two was chaos. Three hundred thousand people showed up. Premier Jack Lang stepped forward to cut the ribbon, and before he could get his scissors out, a man named Francis De Groot -- an Irish-born member of an ultra-right-wing paramilitary group called the New Guard -- rode a borrowed horse out of the crowd and slashed the ribbon with his cavalry sword. He declared the bridge open in the name of the decent and respectable people of New South Wales. Police dragged him away. He was fined five pounds. They had to retie the ribbon so the Premier could cut it properly.

Sixteen men died during the eight years of construction. Almost six million rivets hold the bridge together, each one driven by hand by a four-person team. And the grey paint? Not a design choice. Grey was the only colour available in sufficient quantities. They have been repainting it ever since -- the job takes roughly ten years from end to end, and by the time they finish, the other end needs doing again.

Before he became Crocodile Dundee, Paul Hogan was one of the painters up on this bridge. And a worker named Vincent Kelly reportedly survived a fall from the roadway by dropping his heavy toolbelt into the water first to break the surface tension before he hit. Whether the physics checks out is debatable, but the story has been told on this bridge for ninety years.