London is an unofficial European hub. Even if it is not your final destination, it is cheap, and easy to get almost anywhere else in Europe from there whether using miles or paying cash.
Visit London and Paris on the Same Award Ticket
London and Paris are two of the most popular European cities and so close it is very easy to visit both in one trip. They have history, architecture, and nightlife to offer tourists. And they have another thing in common. They are very accessible from several frequent flyer programs.