Because we were on bikes, and we were in the area, and we could, we nipped in to the church of St Magnus the Martyr, by the north end of London Bridge on Lower Thames Street yesterday, as suggested by Nigel's comment on the recent post Quirky London 9 of 20: London Bridge (rems of).
Its enormous scale model of London Bridge circa 1400 shows that traffic congestion is nothing new. The model has over 900 figures and animals on it; no cattle on today's bridge, and hence no flying poo to dodge, though the odd loquacious taxi driver does their best to provide a metaphorical substitute.
Top tip: the church has a book sale, with a big range of quality, brand-new titles on sale for a quid. Review copies perhaps? Anyway, well worth a look.
The church is open during weekday office hours. On display outside is this remnant of Roman London: a jetty post from Londinium of two millennia ago. They know it was Roman because the sign on it saying NO CYCLING was in Latin.