London Bridge is in London, right?

Come on everybody, sing along with the children's nursery rhyme: "London Bridge is falling down, falling down...".

Is there anything to this? It turns out there is. Not to be confused with the equally famous Tower Bridge, distinguished by its, err, twin towers, London Bridge originally had houses and shops built on it and was in poor repair after standing for nearly 150 years since it's construction in 1831. Yes, it really was falling down, and that really is where the nursery rhyme came from.

So the City of London decided a new one was needed, and to fund this would sell the old one. It was bought by Robert P. McCulloch, a US oil magnate who wanted to use it as a tourist attraction to a new city he founded by Lake Havasu, Arizona. There's no truth in the rumor he thought he was buying Tower Bridge, by the way.

The bridge was purchased for $2.46m, disassembled, and was finally opened on 23 September, 1968 in Lake Havasu City.

Confusion

There was confusion over it's location even before the bridge was moved to the US. The first one was made of wood by the Romans when London was founded, and was in a different location to the one we're all familiar with today, as several wooden ones were built due to each earlier one perishing. Each took a real battering as the city grew, meaning replacements were frequent.

At low tide, there was originally a point in the river between two naturally formed embankments which enabled it to be crossed without needing a bridge. It was still the easiest crossing point  when the tide was high, where a ferry was used. This became the obvious site for the first one, which the Romans built in a pontoon style. The Thames was a way into England from the sea from at least the 9th Century BC, and archaeological evidence of Bronze age activity nearby. It's this bridge which likely was the reason London existed at all, because whilst there was nothing else around apart from this single crossing point, downstream a little shipping settlement that became known as Londinium was built.

1616

Here's an engraving of the bridge as depicted in 1616, with Southwark Cathedral in the foreground. Note the spiked heads of executed criminals above the southern gate!

Built over land

The reassembly took place over land - it was only later the planned canal was dug out under it and flooded.