In a sense it is the oldest bridge in the world — since the Roman era, 2,000 years ago, did some kind of bridge span the Thames river. Where the Romans built theirs, around 50 A.D., a small settlement was established, called Londinium. References around the medieval times talk of a bridge on the location of the old Roman one, but that bridge was destroyed, most likely in a fire. The first, “old” London bridge went up the 13th century, and actually had houses on it: King John licensed them to offset the cost of the bridge. When the population of the city was small, such a narrow channel made even narrow by the house rows on either side did not cause much traffic. But by the 18th century, it was getting to be intolerable.

On this day, August 1, in 1831, the “new” London Bridge opened, not far from the location of the still operational old one (which would soon be dismantled and sold to Arizona.) With much wider arches than its predecessor, it allowed for the passage of large ships below — the recently-constructed HMS Beagle, a 10-gun brig sloop and future home of naturalist Charles Darwin, was the first to pass under it.

The nursery rhyme “London Bridge is Falling Down” may have originated with the destruction of said bridge in the medieval ages. As the vikings were besieging the city of London, Count Olaf helped the Anglo-Saxon king to destroy the bridge, dividing the attacking forces. An alternate, more grislier version goes that the nursery rhyme may refer to child sacrifice, but no archaeological evidence has been found to support it.