Delta is having a 2-day sale on points redemption for flights from Chicago, New York, and Los Angeles (ORD/MDW/LAX/JFK/EWR) to London (LHR) for 36k-38k miles + $189 in tax/fees, round-trip. Flights September to mid-December and mid-January to mid-March. No Christmas.
Note: This destination usually costs about 60k-80k miles.
Note: This is available from most other cities for about 48k miles.
Note: Use the “5-weeks/Calendar View” when searching for your flights, it’s easier than randomly plugging in dates.