Maybe if the weather cooperates and the flight path is similar, you will be able to take a few pictures like this during your London approach. Although there are other area airports, most of the time your London layover will start or finish at either Gatwick (south of Central London) or Heathrow (west of Central London). Gatwick has a north and south terminal, while at Heathrow the terminals are numbered from one to five.
Together, these two airports handle an estimated 100 million passengers a year, with Heathrow ranking first in the world and Gatwick seventh in the world for passenger traffic. Don't assume your scheduled 11 a.m. landing will have you inside the gate at precisely that time. It's also important to know which terminal you'll be entering and how to find your way around each airport. That task is made simpler by two airport websites for Heathrow and Gatwick.