If you are coming to London for any amount of time, you may be interested in a day trip to historic Greenwich.
It’s in south east London, on the DLR and bus routes and trains, and also by river which is great on a nice day, but there’s no real tube station.
There’s plenty to see, including a reconstructed Cutty Sark, the Naval College, the Queen’s House and lots of old pubs and tacky souvenir shops.
If you trudge up the very steep hill you will find the Royal Observatory and wome wonderful views.
You will also find a strip of metal in the ground. This is the Greenwich Prime Meridian. It marks the boundary between the western half and the eastern half of the entire planet.
Every single person who visits gets a selfie with one leg on one side and one on the other, straddling the Earth.