Radisson Rewards members can earn up to 120,000 bonus points for stays between January 15 and March 31, 2019.

The promotion is valid for stays at all of Radisson’s 1,100+ hotels around the world, and offers the following tiered bonuses:
- Stay 1 Night: Earn 1,000 Bonus Points
- Stay 1 additional Night: Earn 2,000 additional Bonus Points (totalling 3,000 Bonus Points)
- Stay 3 additional Nights: Earn 7,000 additional Bonus Points (totalling 10,000 Bonus Points)
- Stay 5 additional Nights: Earn 40,000 additional Bonus Points (totalling 50,000 Bonus Points)
- Stay 10 additional Nights: Earn 70,000 additional Bonus Points (totalling 120,000 Bonus Points)
So as you can see, you can max out the promotion by staying a total of 20 nights, in which case you’d earn a total of 120,000 bonus points, which is an average of 6,000 bonus points per night.
Registration is required prior to your first eligible checkout in order to be eligible for the promotion.
Stays at Radisson Collection, Radisson Blu, Radisson, Radisson RED, Park Plaza, Park Inn by Radisson, and Country Inn & Suites by Radisson are all eligible.
What I also appreciate is that stays booked prior to the start of the promotion still qualify for the bonus, while in the past they sometimes excluded previously booked stays. All that matters is that you stay during the promotion period.
For reference, here’s Radisson Rewards’ award chart, when it comes time to redeem points:

What’s also exciting is that for the purposes of this promotion eligible stays include revenue, free night, and Points + Cash bookings, which is pretty new for Radisson Rewards, because in the past only paid stays typically counted.
Personally I value Radisson Rewards points at ~0.3 cents each, for some context on how much this promotion is worth.