> the Romans planted the walled settlement of Londinium on the marshy north bank of the Thames

Err, I'm reasonably sure that the reason why the Roman settlement was on the North bank was that the North bank was rocky, and the South bank was the marshy one.

The Romans were too pragmatic to try build Swamp Castle ( https://www.youtube.com/watch?v=aNaXdLWt17A )

I was lucky enough to do a programming contract for the museum of London back in the mid eighties when its only site was in the Barbican. We worked weekends in a back room on a pdp11 key:value index.

The museum is a treasure house of the history of London and the archival legatee of many of the guilds and societies.

I usually shy away from gushing recommendations but I think the MOL is one of my favourites, the docklands site was the venue of a conference social one year I went to.. well worth a visit.

Definitely - the Museum of London is sadly under-known in my opinion. I suspect it's mainly to do with being located off the usual tourist track - and even when one gets there it doesn't exactly measure up to the Kensington museums to look at...

It's moving in the next few years to a new site at the west side of Smithfield market. The existing building to be remade into a world leading concert hall for LSO

Amsterdam found out the plague pits were re-absorbed by the city too during the construction of the subway. Trying to imagine what it must be like when a tunnel boring machine hits a mass grave of plague victims, kept me awake at night for weeks.

Amsterdam had many plague epidemics and each time the plague hit 10% or so of the inhabitants died. At least one of the London plagues was traced back to goods shipped from Amsterdam.

The Cataacombs in Paris are cool, I cannot recommend them as an unconventional tourist attraction enough. Just don't try to steal any bones or you will join them... a simple house rule.