The TubeMap app has a journey planner in it which will tell you which station is closest to you, which train to take when you get there, and what stop to get off at or if you need to change trains to get where you’re going.
The Crown Jewels are displayed here. The Yeoman Warders, or Beefeaters, know everything about The Tower of London and they do such a great job making it all interesting.
The Queen’s Gallery hosts an amazing collection of art by Vermeer, Rembrandt, & Van Dyck. You can almost always catch the Changing of the Guards here too.