The Tate Modern is free. It's also near the Globe Theatre, which isn't free, and a bit hard to find. And you MUST go to a West End musical.

Shopping is great, a bit expensive though. Try get to a Jimmy Chow's if you can - the food's fantastic.

I spent a day wandering around the area where I was, just exploring, and that was fun too.

And another fun thing is when random bus tour conductors approach you and start philosophising to you.

We wanted to do the double-decker tour of London but didn't have a chance - ran out of time and money.

Have a great trip!

Go to the Wax museum.... ;)