In my last one dozen visits, the answer for your question, kept changing every time; better, I shall try to make a simple list (with brief explanation, when time permits).
#. However, to me, a memorable show (many shows, run here, at least attend one), which we attended in Royal Festival Hall was amazing!
#. Then, even a walk through the South Bank (Thames) is very relaxing.
#. I am very fond of the collections, of “The National Gallery” [the art museum in Trafalgar Square];
#. Even spending some [photographic] “Golden Hours” in Trafalgar Square is interesting.
#. Surely, not to miss is, Madame Tussauds Museum – it is rated as the best tourist attraction - worth…!!.
Well, let me see (in the coming weeks), whether, I can search out my shots, back.