Yep, theres a whole world out there
Are you only wanting to visit london? Or are you just looking for general ideas on where to go. Europe is incredible diverse, I couldn't tell you all the places ive visited in one post. I'd suggest going on a tour if you want to fit a lot into a trip. Take a look at the itiniarys for european tours by imaginative traveller, they may give you an idea of some of the attractions you might like to see, I went on a trip from Istanbul to Moscow that covered most of eastern Europe, I will definately be going back later in life
Western Europe is different, do some research beforehand, decide how you want to travel. You can get interrail passes that allow you to travel by train across europe for various time periods, they're quite reasonable.