Seeing London from the Thames
The cities that are crossed by a river are more charming to me. Rivers add different architectural elements to cities, such as bridges. Plus they allow you to have views and look at scenery from other perspectives that you wouldn't see from walking the normal streets in that city.
To view London from the Thames, was a different experience for me, which I unfortunately never got to enjoy on previous visits, and luckily, this last time, I was able to.
Of course, the ride along the river is much more relaxing since you don't have to walk. So you can sit back and take pictures in bulk to later share with your family and friends when you return home.