Hyde Park is a good starting point if it's not raining,...
London
Hyde Park
... with the child friendly Princess Diana's playground...
...only a couple of hundred yards from Kensington Palace.
Then there's the funky little Serpentine Gallery not far...
...from the gold-heavy Albert Memorial...
...which overlooks the well-rounded Royal Albert Hall.
Photos left side: Hyde Park bike path running beside the horse sand track; Kensington Palace posh entrance; the Albert Memorial. Right side: Diana's Memorial Playground [no solo adults]; Serpentine Gallery [of odd, modern art]; Royal Albert Hall, used for extravagant concerts and shows.
Information: London Travel Guide
Pictures © bugbog.com