In reply to balmybaldwin: This is easy.
Go to Greenwich. Ansel Adams photography exhibition. Then go to the Royal Observatory and check out Harrisons H1-4. The Cutty Sark is great too, you have the market for art and food. One stop shop and a great day out (you can buy a ticket that lets you into multiple attractions at the Cutty Sark) Also nice views over London from Greenwich park (which all the above is in or next to)