Lots of immigration over a lot of years.
Most of us are immigrants, just a generation or two removed.
What is most truly British is patting ourselves on the back for our fantastic <your attribute here> while assuming this attribute is non-existent elsewhere – though even this isn’t particularly British.
But to answer the OPs question I’d say a trip to a seaside resort (out of season!) would be a mine of photo opportunities, followed by a visit to that London for some jellied eels and middle-eastern food from a pop-up.