Where am I going?

I had the opportunity to work as an au pair recently in Wales but I didn't get the job.
So this was going to be about going to Wales..
but instead my brother, dad and I have decided to take a trip to London tomorrow, just for a week.

I haven't been to the UK for about 5 years so I'd appreciate it if anyone could comment below any suggestions for places to go, things to see etc.