Good luck, hope the trip goes well. In London, theres a kinda one mile square with The Houses Of Parliament, Big Ben, several museums, the London eye and various other sites worth seeing. Lots of the museums are relatively close to each other too, so as long as you get off at the right tube stop, you'll be able to find everything pretty easy and all within walking distance of each other. You can buy a pocket map for about £4 in any newsagent in London, I recommend you do so, its easy to get lost in the center of London, but is also easy to find anything if you have a decent map.
Germany is a wonderful place, I spent several years in Osnabruck, near Munster, and can promise you'll get a warm response from the locals.
ENJOY
